the best place to find that info is XDA forums ...also it depends if you have the exynos or snapdragon chip , you'll probably have more luck if it's exynos.
I don't see any real benefits of doing so as some things not going to work such as Samsung pay.
my advice the note 9 is already customizable :theme store,launchers, substratum it's just not worth it anymore and give up security .
now if note 9 is few years old and no more support I can see going this way .
good luck.