fishing and scuba yes, jetski not. most resorts in the maldives do not offer it. The maldives is all about peace and quiet. most people would not be happy with a jetski in fron of their watervilla. There are some low class party islands, there you will find all of this, disco, jetski, noise.... but thats not what most people are looking for....
Check tripadvisor and halavelis website, it will answer most of your questions....
If you dont have a PADI its not worth doing a "tourist" dive in the maldives. It goes upto a max of 15 feet and costs alot of money, we saw so many fish snorkeling, the water is so clear... we took a snorkeling boat tour costs half and was like snorkeling in a fishtank... sharks, turtles... you name it