They use the Disney buses, which start running an hour before park opening (earlier if there is a morning Extra Magic hour). However, there are Disney buses which will take guests to early character meals before park openings. I think these will also service the Swan/Dolphin. If you can't catch one of these special buses, and the AK opens at 9 with no morning EMH, you don't have much of a chance of arriving before 8. Nor do I know what the protocol is if your breakfast is at Rainforest and not at Donald's, although I don't see it making that big a difference.