Yes the MK boat begins running 30 minutes before park opening. 9 am opening, 8:30 start for the boat. If there's extra magic hours at 8, boat will being running at 7:30. If you get on the first boat and everything is running smoothly, and there isn't a big crowd at bag check, you can get to the MK before opening but not by much. Another option if you want to be early is to take the boat to the contemporary that begins running at 645 am. Then it is a short walk to the MK.