Q: I cant update my ipad to ios9 as my screen wont slide and itunes wont let me update or restore because I cant open my ipad

Hi! Take a look at this Apple Support article:

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

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