[LG Optimus L9 P760, P765, P768, P769] Veran999:
Due to lack of tutorials which contained CLEARLY written instructions on how to root LG Optimus L9 with Chinese method, I decided to write my own in which I'll explain everything step-by-step.

I also found (as I think) a 100% working way to restore normal SuperSU and delete the Chinese one, after resarching on it for about 5 hours.

WARNING: USE INFORMATION AND FILES AT YOUR OWN RISK. You follow this tutorial and use method described here at your own risk.

Step 1: Download and install LG drivers.

Because of the post limit I cannot post direct link to download, but they can be found here, in step 3): CLICK

Step 2: Download and install Chinese root.

a) Download this file: www--mgyun.com/vroot (replace -- with a dot .)

b) Install the software, using the installation buttons as you would on any other windows installation.

c) Connect your phone to your PC with ENABLED USB debugging and select "LG Software" as connection option.

d) Start the program, you will see a green button, press it.

e) When the phone is connected the software will recognise the phone and the green button will show "ROOT", click on it.

f) The phone is going to be rooted in some seconds and the process is finished when it will show a tick on the software.

g) The phone will reboot.

Tutorial taken from this topic: http://xdaforums.com/showthread.php?t=2439667

Credits for it to aristide1997​

Step 3: Download SuperSU application from Google Store.

Step 4: Launch SuperSU application.

a) It'll ask you to install SU binaries. Select NORMAL if you don't have TWRP/CWM installed.

b) A Chinese Superuser prompt will show up, asking if you want to grant SuperSU su privileges. Click the button on the right. Square should be checked.

c) If you followed previous steps correctly, SuperSU should install binaries without problems.

WARNING: It'll ask you if you want to uninstall other applications that are managing Superuser right but DON'T DO IT. If you uninstalled the Chinese Superuser, and now SuperSU doesn't work, go to Step 8.

If you encounter problems (Binaries couldn't be installed):

a) Make sure you have a strange Chinese application in your Application Drawer. It's icon is a shield with a gear inside. If not, go to Step 2 and repeat.

b) Make sure you've clicked button on the RIGHT with SQUARE CHECKED when Chinese Superuser prompt showed.​

Step 5: Exit SuperSU application, reboot the phone.

Step 6: After reboot, launch SuperSU application. If there is no prompt saying that SU binaries must be installed and everything is normal, go to Step 7.

Step 7: Download Root Checker from Google Store and launch it.

a) Check for Root Status in Root Checker.

b) If there is a prompt from SuperSU, asking if you want to give Root Checker su privileges, confirm it and you're good to go. You can uninstall Chinese root.

c) If there is a prompt from CHINESE SUPERUSER, asking if you want to give Root Checker su privileges, just click back (don't confirm or deny). It means there is a problem. Go to Step 8.​

Step 8 (TROUBLESHOOTING):

If you uninstalled Chinese Superuser and now SuperSU doesn't have root rights, go to a); otherwise go to b)

a) If you uninstalled Chinese Superuser and SuperSU doesn't work (saying that binaries installation failed), don't worry. Connect your phone to your PC with USB Debugging ENABLED and start Chinese Root Program again. It should find your device automatically and restore the Chinese Root. Go to Step 4 and repeat.

b) If there is a prompt from CHINESE SUPERUSER to give su rights to applications, instead of SuperSU it means that SuperSU didn't become the main Superuser application and Chinese Superuser still is managing su rights. It can be fixed though.

c) Go to Google Store and download Superuser by ChainsDD (NOT SuperSU. The application you need is named Superuser).

d) Launch it and scroll left. Click on "SU Binaries" with green text in it, under "Elite version is not installed".

e) You should see a console. There should be a red text in it, at the end about "myung" su binaries.

f) Click "Update" button.

g) A prompt will show up, if it's in Chinese click the button on the right to grant Superuser su privileges.

h) New SU binaries will be installed, making Superuser new default application to manage su rights.

i) You can now uninstall Chinese Superuser and install SuperSU or stay with Superuser.​