Hey guys I have also experienced the iOS 9 (slide to upgrade) bug. Another problem was that the phone have never been synced with any itunes so I had no backup.
The most important were the photos in the phone, so I plugged it into my computer, but I got the notice that I have to tap on “Trust This Computer“.
Same thing in itunes, you have to unlock the phone, bla bla.
This is what worked for me:
- Connect your iPhone to a computer
- Hard restart (force restart) your iPhone. If you don’t know how, follow the steps on https://support.apple.com/en-us/HT201559
- Get to the point where you get the apple logo with “loading” bar below.

- Hard restart (force restart) it again
- When it boots up you should get this warning in itunes

- There is “slide to upgrade” message on your iPhone, so you have to slide and after it should ask you for your passcode, enter it and wait till the system loads up
- Then you have to make to a point where you will get something like “Upgrade finished” and “Continue” button.

- In the top bar you should see the top bar with carrier, battery …
- Now you should be able to tap the “Trust This Computer“
- If not, try to make a call with the phone (obviously you can’t make outcoming call, but you can answer any incoming one)
- Now you should be able to tap the “Trust This Computer” and see the iPhone in your itunes
Hope it helped, and feel free to post comments below.