There may be a resort near by, didn't notice. You can also check with your cruiseline and see if they offer anything like that. We did the canopy tour from there and that was a really fun trip, if you are into something like that.
if you just want to hang out at the beach, dont waste your money for a day pass at a resort. Grab a cab at the pier and head over to Dr. Cove Beach. It is a beautiful beach, $5 per person entry fee. You can rent chairs, umbrella's etc. There is a small restaurant/bar on the beach, there is a water trampoline to play on. The facilites are clean.
Make round-trip taxi arrangements, know your drivers name- when you are ready to leave, just go to the reception desk and they will call your cab for you.