The parking gate person should issue you a 3 hour temporary pass to dine. I do not believe you are allowed to park at any resorts for theme park access, which explains the need for the 3 hour pass.
The good thing is that the Poly is reasonably close to the main parking lot at the TTC, in case you decide to either park there before your ADR, or move your car afterward.
Others may have more info, or ideas.