The Aruba Hilton will meet your requirements but can be a little pricey. The AUA airport can be very congested on weekends.
Another option for you is the Hilton in Cocoa Beach/Cape Canaveral, FL. This property has beach, pool, Tiki bar and close proximity to NASA, if that is of interest to the 9 year old. The only drawback to this property is that it is not too close to any large airports.
-Goat