Hi there Aracelis!
Walt Disney World in September can be a truly magical place. Typically, the crowds are a bit lighter, as kids go back to school, and while it is turning fall in many other parts of the country, summer is still in full swing, so you can enjoy the pools and the warm summer evenings.
The regular pass that will get you into the
Magic Kingdom theme park during normal park hours is not the same as the ticket that will gain access to
Mickey's Not So Scary Halloween Party. This is a specially ticketed event that takes place after the Magic Kingdom closes to the regular day time guests.
I highly recommend Mickey's Not So Scary Halloween Party if you can get there. The park takes on an eerie (but not so scary!) vibe, and the park transforms into a Halloween paradise. There are Halloween themed shows and dance parties, a special fireworks display, and an awesome Halloween parade. Trick or Treating takes place throughout the theme park, and you'll even find specialty Halloween treats available for purchase.
Although not every attraction is open during the party, my family likes to use the party as our Magic Kingdom day. Because the lines tend to be shorter, we can usually see and do more than during the day, and the added Halloween fun makes it so worth the ticket. If you do visit the Magic Kingdom that day, you won't have to leave and come back for the party. You can just find a Cast Member with party wrist bands, show them your ticket, and you can stay in and enjoy the fun.
Happy travels, Aracelis!
Anna