No, they don't. It stinks, but the contract you agreed upon when booking states that the cruiseline can change the itinerary at any time for whatever reason.
For what it is worth, I was in Kauai and my friends rented a car to go up to Kea Beach.....and then back again by 2:30. It gave us time to make the scenic drive, grab a burger at Bubba Burgers and get back to the ship in time.......it include about an hour at the beach to enjoy the water, etc. Of course, this depends on weather and ocean conditions.