I have our trip booked with AAA as well, and I'm already getting a reminder when I look at the reservation on the Disney site. I'm assuming that means we will be able to use on-line check in
Yes, you can use online check in, but you won't be able to use it directly from the WDW site (at least I wasn't last year), unless something changed recently. I'm providing the link i bookmarked last September to do online check in with our AAA package:
When we got our conf. # from AAA, it wasn't a typical Disney conf. number, so i asked the agent, and she had provided an AAA confirmation number. She had to go back and give me the corresponding one for Disney so that I was able to check in.
We booked our upcomming trip with AAA. It let me do the online check in but when it asks what building of the resort you would like it gives a message that the request can not be made to call WDW. I was told the agent can put the building request in for you since they "own" the reservation.