You Can Still Downgrade
You can trial the iOS 9.0.1 update on your iPad if you want.
Apple is still signing off on iOS 8.4.1 and iOS 9.0 which means that you can drop back down to either one of those if you decide that iOS 9.0.1 isn't working out. This loophole will only be open for a limited time so you'll need to move quickly.
We've put together a guide that will take you through the downgrade process. Keep the downgrade process in mind for future iOS updates as well.