You can absolutely be dropped off at the parks by Uber (the only exception is MK -- where only buses can drop off right at the park, you can either be dropped off at CR and then walk over or TTC and get to MK via ferry or monorail). The driver (or you) just tell the parking attendant that you're just being dropped off. They usually put a pass on the windshield that says "drop off" and are sent to the drop off location.