Did either of you have "Location Service" or "Find my phone" on?
My wife's 3rd gen Ipad is also bricked. Can't even do a hardware reset on it. She had location services and find my phone/ipad turned to ON.
I did/do have them turned on. I upgraded to ios9 soon after it was released. although I did it through itunes - much safer and better.
i always back up my iphone/ipad once a month, but also especially before any update, and i update it when i am hooked up to the laptop.