Yes, you can rent & use jet skis (or rather Waverunners - the ones with a seat) here, in the center of town on the sea. To get a decent beach you need to go a bit further afield, north or south, but not so far that you can't get into town for a night out and manage to get home afterwards. Even if you don't rent a vehicle (golf cart or motorbike/scooter) there's a good and affordable taxi service here from the town southwards. If you stay north some more care is needed to ensure you can get home.
I don't think there's any fear of you getting bored. Lots of people who come here do just what you're talking about.