you can positively use the pool and the facilities on the day you check out of the hotel.
pack a small plastic bag with clothes.
put it on the top of your suitcase.
check out of the hotel and store your small bag on top of your stuff.
go to the park, come back, take a swim...
go to luggage area and give them the claim ticket and tell them to bring you the small plastic bag tied to the handle of your suitcase.
then, go to the pool room and change, put stuff in locker and head to the pool.
you can use the soap, shampoo, towels from that pool room.
and, you can pool hop to the other hotels pool if you wish.
all 3 hotels have accommodations for the pool guests.
you can not charge on your hotel key at this point but would have to pay cash or cc for any service of food/drink at the pool.
if you arrive at the hotel and your room is not ready, you are allowed to use the pool in advance.
take advantage of that if it is hot....and use the pool room to change.