Can't get back to 4.3 once you've upgraded your boot loader - which it appears you have done with x note 9. look at the TWRP thread and get the version for KK and it should work.
If by some reason your BL hasn't upgraded, then just flash a 4.3 rom.
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The people of XDA, including the Devs. Do not have to help you. We all choose to help. Everyone also starts somewhere.
City I live in makes and invented the Kitkat... I run Kitkat on my device. Aww how cute.