You are best to ask the dive shop these questions. Shoot them an email and they can tell you their policies and practices. Have you made any reservations or are you just hoping they have room when you arrive.
I leave for Playa del Carmen on Friday. I plan to use Tank Ha. I plan on diving at least 2 days in Cozumel, 1 day local in Playa and maybe 1 day in the Cenotes. I'm staying at the Paradisus La Perla near calle 106. Where will I meet the boat? Will they pick me up from the beach? I will go to the dive shop either late Friday afternoon or Saturday morning to make arrangements but, I'm curious about the logistics. Thanks again for the advice.