I would check out the menus on allears.net with your kids and see what you all agree on. I would also consider upgrading your 9 year old to an adult if he really likes to eat, the kids menus are pretty limited. We always like to do a couple of buffets so everyone can choose what they like and our favourites include Tusker House(breakfast), Crystal Palace (breakfast), 1900 Park fare (breakfast and dinner). My kids also enjoy Yak&Yeti, Le Cellier, Teppan Edo and Tutto Italia. Coral Reef isn't bad and the atmosphere is pretty cool. This trip we are trying Cape May for dinner and Whispering Canyon for dinner as our new choices, the rest are repeats. Hope that helps!
I almost forgot about 'Ohana and Wolfgang Puck Express! Also yummy.