I have a son at this level as well. I like 8v8. Don't like 6v6 for this age(u9,u10).
As for cherry-picking a team, I don't see a problem with that. We have a pool of 20 players. The coach picks two teams and they usually play 2 or 3 weeks together then rotate. But if they are going to a strong tournament, I don't see the problem with having a better team in the A division and a weaker team in a lower division (though our coach has not done this).
Pigeonholing a player still happens, though I think that is really based on each individual coach. My son played a whole year on a team where he played one position. Already this year he has played everything but keeper.
