You might have to a private charter to make it work in your timeframe. Contact some of the companies with small fast boats to see if they can accommodate you. Blue Angel, Scuba With Alison, Dive Paradise, Bottomtime are a few you can contact but there are many others.
You can ask Aqua Safari or Dive Paradise about their scheduled afternoon dives but they ususally get back in the 5:00 to 5:30 range and that is cutting it too close to your ship's depature.
P.S.
This is on the Aqua Safari website:
[FONT=Trebuchet MS, Arial Black,COZUMEL,scuba,diving,cozumel]ONE TANK AFTERNOON DIVE $35.00 US
2:30 p.m. to 4:30 p.m. One tank shallow dive (Paradise Reef), includes tank and weights, divemaster and sodas and purified water. Usually done from one of the large boats.[/FONT]
The price maybe out of date and you still might want to check out private charters to lessen the chance of problems.