Hi! Each and every Apple Support article as well as the tutorials from third party sources point out that it is recommended to backup the data on the device before performing any actions with the firmware (restore, update etc.)

You can let Apple know about your idea.

https://www.apple.com/feedback/

You can also describe your problem in more detail, so that users on this forum can help you.

Unfortunately, the latest update caused various problems to many users. Normally, everything works just fine.

Maybe the steps below will somehow help you.

Hi! Take a look at this article.

If the Slide to Upgrade screen won't go away after you update to iOS 9 - Apple Support

If this doesn't help, try the steps below.

Try to reset your device. This won't delete your data stored on this device.

• Press and hold the Sleep/Wake button
• Press and hold on the Home button
• Keep holding both buttons until the display turns off and back on with Apple logo on it.

Alternatively, you may go to Settings - General - Reset - Reset All Settings

https://support.apple.com/en-us/HT201559

As a final step, try the recovery mode. Turn your device off, then plug it to your computer with the home button pressed. Keep the Home button pressed until you see the iTunes logo on the screen of your device. After that on your computer you should see the iTunes window saying your device needs to be restored to factory settings. Click on the restore button.

More info here:

https://support.apple.com/en-us/HT201263