Also see how to root your Tecno Camon C9 Here
=>first, before we begin, we have to enable USB debugging on Our Tecno Camon C9 smartphone, to enable USB debugging mode, go to settings>>click on about>>continuously tap on the build number continuously for five (5) times to enable debugging mode.
=>next thing is to go to settings>>click on developer option and enable OEM unlocking.
=>after which, setup ADB and fastboot on your PC.
=>now connect your Tecno Camon C9 to PC via USb cable.
=>after which launch your ADB and run the command provided in red below and press "enter".
=>the work of the provided code is to make sure if the ADB detected your device.
=>now input and run the command provided below so as to boot your Tecno Camon C9 into fastboot.
=>after which your device will boot into "fastboot mode" after which your screen will go black and you "fastboot" will be written on it.
=>after which type the following command below and press "enter"
-=>after which the code above will prompt your device asking you to confirm the "bootloader unlock"press the volume up button for yes.
=>wait till you get a success message, after which input and run the code below to boot your Tecno Camon C9 into system mode, system mode also means the normal working device mode.
Congratulations, you have successfully unlocked your bootloader of your TECNO Camon C9.