If I were you, I'd drive.
That's a tricky priority seating time. Magic Kingdom bus service starts at 7am, so that wouldn't work.
If you drive to the contemporary though, they'll probably issue you a 3 hour temporary parking pass, which then means, you won't be able to get to the magic kingdom without moving your car. You can either park at the TTC, and take a monorail, or drive back to pop century and take a bus back to the magic kingdom.
Good luck!