Hi Corie!
Congratulations on your upcoming vacation!
September is a great time to visit - one of my favourite times as a matter of fact!
With 4 1/2 days to spend in the parks, and children as young as yours are, I'd recommend that you plan on two full days at Magic Kingdom, a full day at Hollywood Studios, a full or almost full day at Animal Kingdom (with perhaps some resort pool time), and a half day at Epcot.
All four parks have plenty of attractions and shows for the whole family to enjoy together. Be sure to visit the
Attractions page to read about attractions with no height restriction at all of the parks.
If you'd like any recommendations on must-do attractions for pre-schoolers or great Character Dining options, feel free to ask away! We always love sharing our own experiences and recommendations to help ensure you the best possible experience at Walt Disney World to suit your family's tastes and needs!
Wishing you a simply Magical time with your family at Walt Disney World Corie!
Kirsten