Hi-
I was there in October and I think the MK boats started 30 minutes before opening- so 7:30 for an 8 AM EMH and 8:30 for regular 9:00 days.
However, you could still either take the small boat to the CR (that runs from 7am -10pm I think)and hop the monorail or take the bus to the TTC and hop the monorail.
We did the TTC to Monorail for an early PS and it was quick. Left Lodge at 7:30 and were walking down Main Street by 7:55 am.
Have a great trip!