Q: iOS 9

Does anyone know how to fix problems caused by ios 9?

Since downloading iOS 9 on my sons iPad 2 my son can no longer access his iPad.  The iPad has a message "swipe to upgrade", but the swipe action is prevented. After holding down the home button & on switch (for 10 seconds) the iPad restarts with the usual apple icon & the whole process starts over again. Sometimes the iPad asks to enter the password. Once entered, the apple icon appears again then the word hello appears with the message "slide to set up". Password entered again & then the message appears update completed. "Continue" in blue appears, then back to the start again. The Apple icon appears, "slide to upgrade". The software keeps going around in a continuous loop. Never progressing in completing the update. Does anyone have a solution?