I had this same exact problem after updating to ios 9.0.2 but not from earlier versions of the software.
I tried and failed with rebooting, restoring network connection, turning airplane mode on and off and restoring my phone through iPhone settings and through iTunes.
I'm not sure if this was said but here is the solution that worked for me after trying a million other ways!!
*If you are able to, backup your phone before you try this*
1.Turn off iPhone
2. Open iTunes on computer
3. Hold down HOME button on iPhone THEN plug into cord that is connected to computer with iTunes open while STILL HOLDING HOME BUTTON
- you should be holding the home button down before you plug it in not after, and keep holding it
4. You will get a prompt to restore the phone - click "Restore iPhone on iTunes"
You will then have to restore your phone from a past backup - hopefully it was recent!
I hope this helps because it took me a long time to figure this out and I was about to go to apple
**sorry for the caps lock I just needed to emphasize some important points here 🙂
P.S. I have the iPhone 5