Should I update this iPad 4 to iOS 9?
I have a trusty old iPad 4, which gets heavy use, that never got updated past iOS 6.
Of course, it's now too late to bring it up to speed with 7 or 8. Should I attempt to update it to iOS 9, or just let it live out its life as a happy iOS 6?
Having this iPad working properly is pretty critical for me right now, and I can't afford to risk having it bricked or borked or slowed down. (It also has an old battery that hasn't got maximum life left in it, so that's another factor.)
Has anyone had any good or bad experiences with an iPad 4 running older software, updating it to iOS 9?
MacBook Air (11-inch Mid 2013), OS X Mavericks (10.9.1)