Don't Install iOS 9.0.1 If You Aren't Prepared
The iOS 9.0.1 update is a small update but even the smallest iOS updates can have a major impact on overall performance. That's why you're going to want to be extremely careful.
If you haven't done at least a little prep work ahead of your install, you're not going to want to install it. At the very least, you're going to want to make a backup to ensure that you come out of the installation unscathed with all of your files.
If you're coming from iOS 8 or something older and you haven't done any prep, you're going to want to spend a day, at least, getting your brain and your device ready.
Fortunately for you, we've put together a list of things to do before installing the iOS 9.0.1 update. We've also pieced together a list of iOS 9.0.1 upgrade tips. Take your time and don't rush into the iOS 9.0.1 update if there's no need.