The pool and the swim up bar do receive shade as the day progresses. Depending on the time of year, in the morning from about 10am to about 1pm, the pool is usually in full sun. As the afternoon begins to wane, there is plenty of shade on the pool and at the swim up bar. Also, there is a thatched roof over the swim up bar and the bar stools in the pool are shaded.
redinthehead, I'm sure you know this (based on your name) but here goes anyway. Use a waterproof sunscreen, it will stay on longer. The water magnifies the suns rays and you can actually get burned in the pool. So make sure you reapply often. Your going to have a blast!