Technically, no. When you get to the 'guard shack' at the Polynesian you will be asked for your ADR time, and given a temp. parking permit...for about 3 hrs. Then you are supposed to have finished eating or touring the resort within that time period and left. There have been reports of them towing cars that have 'overstayed their welcome'.
I would park at the TTC and not have to worry about it. If you are staying on-site then take your resort bus to the MK and use the little ferry to get to the Polynesian for lunch and monorail back to the MK for the afternoon.