It really does depend upon your skills level and sight reading ability. If you want to accompany, there may not always be time to have an advance look at the piano part. You could play in Care Homes, where I have quite frankly encountered some very low standard pianists who get away with it because no one expects much in the first place.
Poipu: Sunny Side of Kauai - See 72,655 traveler reviews, 6,044 candid photos, and great deals for Poipu, HI, at TripAdvisor.
General Weather. Hawaii's dry season runs from April to October, so you should stay dry in September, but this depends a bit on which island you visit. Kauai always sees some showers in September, but the rain mainly occurs in the north and in the mountains, and showers are brief. September can be one of the hottest months in Hawaii, with hurricane weather systems causing humidity in the region.