nodakdive
Contributor
To do a morning and afternoon 2 tank, you need to be on the boat by 730AM or the latest 8.
With surface intervals and travel you are looking at 4 + 4 hours min.
I've done a lot of 4 tank days with Deep Blue. As you noted, they leave at 9am. They, like other shops, will drop you at a beach location after the morning 2 tank trip, usually Paradise Beach or the Money Bar, and then pick you up there after lunch for the afternoon 2 tank trip.