I have only done Coronado Springs out of the three mentioned and it is our favorite resort!
If you are doing Disney and pool time, you can't go wrong here. Some of the best transportation on property! The pool area is too good to be true! Your 9 yo wll love the slide and the kiddie pool is right there for your 3yo, plus a great playground and game room right by the pool. The pool bar also has food for a perfect afternoon poolside!
The food court is very nice in that you are seated and your drinks are brought to you . You pay after your meal, which means no balancing trays and drinks while waiting to pay and trying to watch little ones at once!
The rooms have a coffeemaker with mugs and complimentary coffee, iron and board, hairdryer.
The whole reort is beautiful and there are three "themed" areas to choose from. Cabanas 9B is convenient to the food court and and pool. There are four bus stops around the resort. Don't bother with a car. Your 3yo will need a stroller. When we stay onsite with our son we head to the parks for opening, come back for a swim and nap after lunch, and go back to the parks in the evening. It's very easy using the buses. Have fun whatever you decide! check mousesavers.com for discount codes.