I wasn't aware you could drop off a car there after they close. You can't really walk to anything from the CCC and the shuttle stops running when they close for the night.
If you need to drop a car off after hours, you could select the Dolphin as your drop off location when you book your rental. The valets there will take the keys and issue you a receipt for the car.
If you want to see where the CCC is relative to the TTC, go to Google Maps and enter this: Car Care Center, Car Care Drive, Bay Lake, FL