9 week puppy

Question
we purchased a german shepherd puppy after months and months of reseach and checking millions of references on breeders.  finally i found one, bought a puppy who is now 9 wks and so far have not regretted it.  he is wonderful.  however, one question.  my husband would love to wrestle with him and has a few times, but it causes him to play bite more often than he usually does when told no all the time for it.  is there a way to teach him to play (wrestle) with my husband only and not use his teeth in anyway with me or our 10 yr old daughter since i dont want him growing up and misusing his strong jaws and teeth?   i suggested to my husband that we need to wait until he is older and trained so he knows the difference?  

Answer
At that age, the puppy needs a very consistent message of no teeth on a human hand.  Your husband can still wrestle with him, just not let him bite.  

We recently attended a training seminar where the nationally known trainer suggested that yelling and walking away is the most effective way to get the no bite message across.