When you're not afraid to lose all data on your iPad, this will certainly work:
- Download an IPSW (from https://ipsw.me/9.2.1).
- Connect iPad to PC/Mac
- Put iPad in DFU mode (press Home + on/off button until iPad goes black; wait 5 seconds then release on/off button, but hold Home for 20 more seconds).
- in iTunes click Restore (with the ALT button pressed) and select the downloaded IPSW.
- let nature run its course and you're good to go after 10 minutes or so
- reinstall all your apps (manually)
- (and when asked "there is a new iOS update 9.3" do not install it!)
The loss of data is a PITA, but at least your iPad is no longer bricked.