This really is AmoDolphin.
I am ten and I still love Disney. I went when I was nine and it was still VERY magical. I have been about eight or nine times. We go once every year (roughly). Last year, when I was nine, it was in November and I faced my fear and went on Splash Mountain!

:

If you are going in Jan, you still have time to make res. to the Castle for a meal. You might not have any chance, though. The best things to do (if you are nine) are:
The Mt.s (mabey not Space. I don't know her personality)
Also, Buzz Lightyear, Micky's Philhar Magic, and Pirates of the Carabiean. She might still have fun on: It's a small World, Peter Pan, Dumdo, and Aladin. Dumbo and The Carasal are always magical too.
For Epcot, There isn't much. I have not been on Mission:Space yet, but Test Track is a must see. I remember a Norway flume, but I haven't been on it for a while.
MGM, This year, Jan, I faced my fear and went on Tower of Terror. I ABSOLUTLY HATED IT!!!!!!!!! If I was nine, I would probibly screem and yell and push against the door. In other words, no. I would rate it PG-13. Also there is scarry atmosphere. Then there is Rockin' Roller Coaster. I have never been. (Note from Amo's mom: this is Amo's preference. She's not a roller coaster fan. Her brother started going on these rides at 8, and has always loved them. It depends on the kid.)
We didn't go to Animal Kingdom. For the whole park, unless you must, don't go. go for another day at Magic Kingdom. The have some nice rides: Kali River Rapids, It's Tough to be a bug, and Kilimanjaro safaries. Other than that, It's mostly trees and animals (African, Asian, Rinos, birds...etc....) (Another note from Amo's mom: We go frequently, but usually only for a day or two. Animal Kingdom rarely gets squeezed in. Next trip I want to stay for 4 or 5 days, and we WILL do AK.)
I have never been to the water parks, but they sound fun. In Typhoon Lagoon, they have a place where you can swim with sharks, but I think you have to be ten or eleven.