Might depend on the ship. Haven't had an issue with food or pools on Allure/Harmony/Independence out of Port Everglades.
I will say that Allure and Harmony seemed to have a longer wait to get on board. Which makes sense, given how many people can travel on the ship. Indy there was no waiting time at all.
Also, once you get an assigned boarding time after check in, you can safely ignore it as they'll let you board whenever you get there.