Housebreaking

Question
Hi,
I'm at my wits end. I have a 6 year old femaile german shepherd and an 8 month old male german shepherd. The problem is with the male. I got him at 4 months. He's doing pretty well with housebreaking when I'm home and available. The problem is when I'm in the shower or on the phone and don't take him out right away, he'll go in the house. He usually goes in the one spare bedroom, so I put a tarp on the floor to try to save the carpet. The biggest problem though, is I live alone and work full time, so I'm gone for about 9 hours or so. Every night when I come home, I find he pee'd and pooped on the tarp in the bedroom. I've tried leaving no food and little water, but that doesn't seem to matter. I've shown him and reprimanded him, then ignored him for awhile afterwards. What I don't understand is, for the first couple of months that I had him, I left him blocked off in the kitchen and he never went in the kitchen, so why is  he going in the bedroom? I'm sorry this is so long, I just thought the more details, the better. By the way ... he and my other dog get along very well. Thanks you for your help.

Answer
Better a long question I can give an answer to than one I have to address several possibilities.

9 hours is a long time to leave dogs by themselves.  I think one of the best solutions for dogs like yours, is doggy day care.  Much more fun to spend the day running with other dogs. If you can't do that, look at some way of giving them a break mid day, come home for lunch, a neighbor, a professional dog walker, anything you can find.  

The last resort is to crate them for the day.  Other dogs may
not be as bad as the young Labs I am plagued with.  Still your house and dog
will be much safer with the dog in a crate when you are away.  The dog may be
happier in its den than loose in the house.  It relaxes, it feels safe in its
den.  It rests, the body slows down reducing the need for water and relieving
its self.  Dogs that have been crated all along do very well.  Many of them
will rest in their crates even when the door is open.  I think the plastic
ones give the dog more of a safe, enclosed den feeling.  They are harder for
dogs to open too.  Metal ones can be put in a corner or covered with
something the dog can't pull in and chew.  Select a crate just big enough for the full grown dog to stretch out in.

Leave it some toys.  Perhaps a Kong filled with peanut butter.  Don't leave
anything in the crate the dog might chew up.  It will do fine without even any
bedding.  You will come home to a safe dog and a house you can enjoy.

A dog that has not been crated since it was little, make take some work.
Start out just putting its toys and treats in
Shepherds can go longer that some other breeds.  When he was shut up in the kitchen, he may have held it not wanting to foul where he was shut up.  He may not see much difference between the spare bedroom and outside except he has access to the spare room through the day.  No shutting him in the kitchen is not the answer.

The "shut the puppy in a safe room" is a fallacy.  Very few houses even have a
safe room.  How many of us have a room with a hard surfaced floor and nothing
else?  Most rooms have electrical cords to chew if nothing else.  In addition
to destroying anything a bored puppy finds to chew, it may choke or have
intestinal  blockage from the pieces.  I had a friend that left her dog in a
"safe" room.  It ate a hole in the floor covering.  The safe rooms fail to
give the dog the comfort of the enclosed space their instinct requires.  Nor
do they restrict activity extending the time the dog can go without relieving
itself.