Hi Sarah,
Of course you may make room requests regarding your stay at Disney's Polynesian Resort. I just stayed there in January and loved it! I bet your family will enjoy this tropical island paradise too.
Sounds like your kids are at a great age to enjoy the
Nanea Volcano Pool at the Polynesian. If you want to be as close as possible to this feature pool I would request a room in one of the following longhouses: Samoa (the closest), Niue, or Rarotonga. Rarotonga is also a superb location because of its proximity to the Great Ceremonial House, where you will find the monorail station, restaurants, and gift shops.
To make your room request, simply call your travel agent (if you used one) or Disney directly to have them make note of your preferences. While room requests are not guaranteed, I know that the cast member who assigns rooms will do everything in his or her power to honor your request. Be sure to ask again at check-in to see if your request was noted on your reservation.
Have a blast at the Polynesian!
Jill