You should call CRO to find out which resorts have AAA-discounted rooms left, for your dates. They only set aside a certain number of rooms that they'll give the discount to. This is not only Disney, all hotels only discount so many rooms for AAA.
We already have AAA, so when I call to make a reservation, that's the first thing I ask about. Depending on the resort and number of nights you stay, the AAA discount can save you quite a few dollars
If you do book a AAA discount, be sure to have your membership card with you at check-in. A few times I've been asked for the number when I've made the reservations, but I think if you told them that you'll be joining AAA, they should still let you book the room.
Hope this info is helpful