From MGM, you can take the Ft Wilderness bus directly. Once at Ft Wilderness, you may have to change to an internal bus to get to the Pioneer Hall area. You can ask the MGM bus driver about this. Alternate ways are to bus to the MK ( assuming MK is still open at the hour you're travelling ) and take a boat to Ft Wilderness from there. The boat will drop you off about a 5 minute walk from Pioneer Hall.
I've never been to the 9:30 show, so I don't know if they have resort busses running from Ft Wilderness at that time or not. Maybe someone else can check in with that info. Have a great time!