I had an ADR at about that time in the morning on a day the MK opened at 9. I was also staying at CBR. I caught the bus at about 7am, and the only people on the bus were going to breakfast reservations at either the Poly or the Contemporary. The bus driver did not even go to the MK; he only went to the Poly and the Contemporary.
So, this MAY be an option for you, but don't count on it. When you get on the bus, ask the driver if s/he can take you to the Poly. If not, just get off at the MK and take the monorail or the boat over to the Poly.
Disney World: 10/92 Yacht Club, 11/96 Disney Institute, 12/00 Yacht Club, 6/05 Beach Club, 8/06 Shades of Green, 8/07 Caribbean Beach Resort, 10/07 Coronado Springs, 12/08 French Quarter, 3/10 All Star Sports, 4/12 Port Orleans Riverside
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