My AT&T 64GB iPad Air 2 with iOS 9.1 will not turn off. It doesn’t matter how long I hold the sleep/wake button down or hold the sleep/wake button and home button simultaneously. It won’t power off. The slider to power off never appears and the force reboot never works.
I allowed the battery go to zero percent so the iPad “powered off” with the hopes that a shut down would resolve the issue. It didn’t. After charging it and powering it back on, I still cannot power it off.
I reset it to factory defaults, hoping a reset would resolve the issue. It didn’t. It still won’t power off.
This appears to be a bug in iOS 9 that wasn’t resolved in iOS 9.1 based on when posts about this issue started to appear.