Hi Rhonda!
You can absolutely make everyone ecstatic at Walt Disney World! There is something for everyone!
The ages 7, 9 and 5 actually work well together. There are many attractions they will all enjoy, such as
Dumbo, Jungle Cruise, Spaceship Earth, the Seas with Nemo & Friends and Toy Story Midway Mania.
You can search for attractions based on
height restrictions on the Disney website. There are many attractions that do not have height restrictions, meaning that all can enjoy the attraction! All four parks have wonderful experiences that your entire party will enjoy. Make sure to enjoy the parades, Wishes at Magic Kingdom and exploring the World Showcase at Epcot. At Hollywood Studios they will love the Star Wars theming and attractions. I have a girl and a boy and they often find common ground at Walt Disney World because there are so many attractions that offer something for both of them.
In regards to what to bring, make sure to bring bathing suits so you all can enjoy the pool. I also like to pack a Camelbak, which is a backpack that also holds water. I can carry around my phone and essentials in the backpack portion and have extra water for the hot days. Make sure to pack comfortable shoes and thick socks as well because you will be doing a lot of walking.
Magically,
Stacy