Step 8 – Once finished, tap on the ‘Install’ button from the list, choose the Magisk-v18.0.zip file that you copied to your phone memory in Step 3.
Step 9 – Confirm installation on the next screen by swiping on the “Swipe to Confirm Flash” option. The installation procedure should start now as show below.
Step 10 – Once the installation is completed, you will be shown a similar screen like shown below.
Step 11 – Now, do the same from Step 8 onwards for the second file (no-verity script). Once that is done, simply reboot.
That’s it! You should now have a rooted Galaxy Note 9 device. You can go to MagiskManager app to verify.
To make sure you have correctly installed the above root method and it’s working, verify with Root Checker as given in the link.
Have fun playing with it! If you have any issues, please fire them up in the comments below!