9 month old male lab...dominance and possible aggression

Question
Hello. This forum looks very imformative and empathetic so I am hoping to get some sound advice. I have received much advice in the last couple weeks and am really at a loss of what to do. It's one of those things when your heart says one thing but your brain, trying to be logical, is saying another.

We brought home an 8 week old male lab puppy after carefully selecting him from the breeders. He is almost 9 months old now and has been a constant source of stress in the household which is evolving to fear at this point. From day one, he was never one of those dogs that loved to be pet, held, cuddled, it was always met with biting (which I attributed to "puppyhood" and gave the corrections of ouch, no, ignoring, etc. He also got in to and still does of his fair share of puppy michief (garbage, peeing in house, etc and I am willing to accredite some of that to "puppyhood".
The scary behaviour is that he is constantly biting me, my husband, and whoever comes over to visit. he is NOT breaking skin but leaving teethmarks, briuse marks, etc. He will jump up on someone entering our patio and start this nip/biting. When given a correction he only does it more. It has gotten to the point that I will not leave him around our two young children and will crate him when we have company. He has been thru 12 weeks of training with a very reputable trainer who picked out some dominance issues when he wouldnt heel, walk.. etc. He also was very hard to toilet train, and still will come in after being outside and pee on floor or to my husbands dismay he jumped on the bed with my husband in it and peed on him yesterday morning. I know I am dealing with severe dominance issues because of other factors that are far too many to list but it is the biting that scares me. I keep trying to think that he is still a puppy but he should have some fear of us, especially when he is given a correction, which only makes it worse. He thinks he is the alpha male and we just cant seem to cure it. So....here is my situation...
I called the breeder to inquire if any other in the litter had come back with temperment issues and he said no but asked me to describe the behaviour. After hearing it, what I was referring to mouthing, he said is biting and that this is possibly uncorrectable and that he would replace him with another puppy as per the gaurantee. He said that I have to think outside the box acting like this now after training, no tug of war hitting, no cruelty, etc, then it can only get worse and that I could end up in a big lawsuit OR worse, him attacking one of our kids. In my heart I know this is the best option BUT I also know that I hold his fate in my hands and that he will not be us rather probably put down.
I have been working with my trainer who says that the last option in the bag of tricks is to use the e collar(shock collar).He says all dogs are trainable
I am rather against it because from what I have read they can furthur aggression and can turn the dog against you as you give the correction or what he associates the correction with. BUT, as a last chance I have used it for the last couple days and on day one he had no reaction to it, I know it was working because I used it on myself before him to know what he would feel. Yesterday, as he started biting at my arm I gave him a correction with it and he growled(not baring teeth or lips) and bit again, He repeated this 3 times with each correction. Today, it seemed to work on things like the garbage, counter surfing, etc, But these behaviours are not really my main concern although I know they are all intertwined with dominance.When correcting teh biting I think it makes him more angry/fearful, etc
My husband wanted me to surrender him to the breeder weeks ago but is giving me these options until now. He is completely fearful and says he is tired of watching me try to get this yellow lab to be that people and kid loving dog that he should already be, and that if at 9 months he is acting this way, in a few more, he may attack our children. That is of course becoming my secret fear as well, yet, I am trying not to give up.

I have called a few humane societies because i would rather lose the money than know he may be put down but they will not accept him because he is a liability, and tell me that the more humane thing would be to put him down rather than the punishment he may get after attacking someone and that he would then get put down anyhow. I thought of selling him a month back, but know that even being honest with potential owners, that it is still a liablity in case this is true dominace aggression.

I really know the writing is on the wall but am grasping at straws, at success stories, etc.  he has been checked at the vets nd there are o medical conditions present to warrent this behaviour.

I just dont want my dog to wear a shock collar for the rest of his life to prevent a disaster when I know that with my previous 2 labs this was NEVER an issue. And my female that is still with us is 9 and has never put her mouth on anyone. My trainer said that maybe he acts this way because the home is busy with two children BUT the 9 year old has never displayed this behaviour and I am sure never will. My husband says that the trainer will say anything because he doent want to see a dog possibly put down but where will he be in 2 years when he bites someone.

Thats about the jist of it and if you've stayed with me this long I really really appreciate it. It's just come to a desperate choice for me as my husband wants him gone like yesterday, the trainer says keep trying, andI am really cut in two. I look at him when he is sleeping in his crate and think...he looks so swet and he will lick you a lot when you reach in there to pat him, It's when he's out ...he becomes a terror lol
 As well, my mother , who is a dog lover as well and has owned previous male labs, says she thinks there is just something off about him, and that for the first time in her life, she feels distrust at a dog when she comes for visits.  Could this all just be a phase...well I guess a 9 month one.....

Thanks in advance  

Answer
If your trainer is using physical corrections on this dog, I urge you to find another trainer and to stop "correcting" the dog yourself.  Do NOT use a shock collar on your dog.  Firstly, aggression met with aggression causes more aggression, not less.  What really needs to happen here is to have the dog understand that you are in charge of all his resources - then, and only then, do you become important to him.  What you should have done is to have gone to puppy class WITH the dog, not turn him over to someone else to train, who could be using pinch collars, shock collars, and leash jerks, which only make the dog more pushy or more anxious, either of which could lead to more of the behaviors you do not want.  It's almost as if you have abdicated the throne in your household and let the trainer take over, when the trainer should have been showing you how to become a BENEVOLENT leader in the home.  For example...I have a pushy little Aussie, who was pushy at age 10 weeks when I got her.  So, right away, the first thing I did was to hand feed her for a week.  Next, I taught her that if she would "sit" and "wait" the food dish got lowered to the floor, and she got dinner.  But, if she did not sit and wait until it hit the floor, I took it away - too bad.  Fifteen minutes later, I'd try again.  If she did the sit and wait she got fed, if not the dinner went bye bye until next day.  Right now, it sounds like the dog is in charge, and, especially as an adolescent dog, this should be discouraged, but by training and management that is not confrontational, such as I just described.  In my opinion, you should change trainers (I would not use anyone who would suggest putting a shock collar on a dog - you will make things much worse IMO), and consult with a behaviorist with either a Ph.D. or DVM credential from the Animal Behavior Society, or someone from IAABC.  I'm not sure that you can't salvage this dog, but you need expert advice in person, not from an internet conversation, and you need to stop any form of aggression toward your dog right now.  Crating him is fine, and muzzling him for your peace of mind, even if it's temporary, is also fine (be sure to learn how to acclimate him first), but shock collars are not fine as a treatment for aggression, and mostly just make things worse.  To be honest, this sounds more like a pushy dog than an aggressive one - aggressive dogs generally bite, pushy ones mouth you (and dogs have excellent capacity for inhibiting the bite - if he wanted to sink his teeth he would do it and it appears he is rude, but not intending a bite), push through doors first, bark at you to give them treats or toys, nudge you or try to push you out of the way, may mark your personal items, or try to keep you from patting the top of his head.  The cure for it is NILIF (Google that) and the proper type of obedience training.  I like clicker training because it is both non-confrontational, and effective if done properly.  Try the attention exercises at www.clickerlessons.com.  This is a dog that needs structure, but not force, which will only produce resistance.  Reinforce what you like and ignore what you don't, plus make him earn his privileges!  To me, it sounds like you got a dominant pup and then did not fully understand how to manage him without force, which usually makes them worse.  Very few dogs are really born with a screw loose, and this dog is at an age where, if he does not understand his place, he will just do as he pleases.  It's time to change that.  I hope you will take advantage of the suggestion I made about the behaviorist.  IMO, it's not ok to put a dog down, or surrender him to the breeder, without getting educated advice from someone at that level.  Good luck.