Brenda, there are a couple of excellent spots for beginners on Kauai. First of all, Kalapaki Beach (inside Nawiliwili Harbor and within easy walking distance of the ship) offers several areas for beginners. Go to the Marriott Resort and Duke's Restaurant on the beach and see if the activities Director offers surfing lessons. I would think that they would and you wouldn't even need a car.
The other place that is excellent for beginners is Poipu beach and the breaks named Waiohai and First Break. Check out http://www.kauai-surf-lesson.com
for info about surf lessons there.
Surfing is the essence of life (from a hard-core surfer) so enjoy every minute in the ocean.
Have a great cruise!