Honor 9 STF-L09 root method is now available For EMUI9.1. This is a universal root method and compatible with all variants of Honor 9. But getting the bootloader to unlock the code can be a complex task because the phone needs to be downgraded. The phone needs to be on the June 2018 Patch level in-order to get the bootloader code. Just like EMUI8 bootloader unlock will wipe all data on your phone. The root method we will use in this tutorial is Magisk.
Disclaimer: Everything you do at your own risk, i am not responsible for any bricked devices.