Right, I want to update to 9.0.2.
Oh! OK.
Here's how I'd do it then.
1. Download latest version of the new jailbreak.
2. Plug phone into iTunes. Back up.
3. Shut off your iPhone (with it still connected to your computer and iTunes open).
4. Put your phone in DFU mode.
5. When iTunes detects your phone in recovery mode, upgrade and restore.
6. Set your iPhone up as new. Skip all the crap (iCloud, passcode, TouchID, etc) the phone asks and just get to the springboard.
7. Still, with iTunes open (not technically necessary but a step I've adopted), run the jailbreak as an Administrator (I am assuming you are doing this from Windows).
8. Do what the JB program instructs you to do.
9. When your iPhone has done the final reboot, disconnect from your computer and open Cydia. Let Cydia do it's thing.
10. Reconnect your iPhone to iTunes. Restore from the backup you made in step 2.
11. Once all your apps have redownloaded you're done.