Is there time for StingRays and land tour?

We are there 8-4. I was wondering is there time to do both

Yes, many tours offer both Stingrays and some other "land" portion like Turtle farm, Hell, beach etc. What type of land tour are you looking to do?

Most Stingray operators will drop you at Seven Mile Beach after your tour if you request that.

Does anyone know of an operator that does stingray city, snorkeling, and the turtle farm?

Part of this depends on your ship's itinerary. Ours was rather short, so we did this combo as a ship's package deal. There are a bunch of operators that do the stingray city and snorkeling. I'd honestly check them out and go from there - if you have time, you can also catch a bus out to the turtle farm. If your time is short - like if you take your ship's arrival and departure time frame and subtract out two hours for tendering and ship clearance, and then an additional hour or more if you aren't in a suite class with priority boarding (check your cruise board for insights into how long that would take), and you come up with less than 5.5 hours, then it's not going to be easy to do it all.