If you're playing with AS50's then just stay with them, they're good enough for professional use as well. There is no point in social players using F90's and I can't think where to buy them.
They always use special shuttles for the Olympics. In 2008, a German commentator mentioned that several nations asked to get some for training purposes, but were denied....they're used exclusively for Olympic competition play (at least that's what he said). I don't think we'll notice any difference to AS50s which are already of superb quality and also incredibly expensive
There are 2 type of shuttle in use at the Olympics. Yonex Tournaments Yonex New Official Each athlete is supplied with a tube of 1 Doz Yonex Tournaments to practice with on arrival at training in London. When they break them they have to use what they have left. I don't know where the New Officials have came from but there has been a few of them about.