Load/response times have increased
My iPad 2 running iOS 9.2.1 has gotten very slow to open/load/respond. Opening a book, facebook page, etc. can take several minutes. Answering emails, the screen lags noticeably behind the keypad.
iPad 2, iOS 9.2.1
These are basic troubleshooting steps that might help. Give them a try in this order.
For Safari ...Go to Settings>Safari>Clear History and Website Data
Close all apps. Press the Home button two times quickly. You'll see small previews of your recently used apps. Swipe left to find the app you want to close. Swipe up on the app's preview to close it
Now, force restart. To force restart your device, press and hold both the Sleep/Wake and Home buttons for at least ten seconds, until you see the Apple logo.
If that doesn't help, try resetting all settings. Settings>General>Reset>Reset All Settings. No data is lost when you do this, but all device settings have to be entered again, including your WiFi network passwords.
There are other stores that you can take like restoring a backup and/or restoring as new, but try the easy steps first.