Is 九 a radical or a component?

While this advice may be more relevant for you towards later levels, a particularly helpful resource when learning a new radical or kanji on WK can be this userscript adding semantic-phonetic compositions. It really helps point out a component that WK might have broken down more elaborately as radicals and gets you looking at those patterns as another hint to what their reading might be.

Whenever I encounter a new radical or kanji and I see some sort of differentiator, I make sure to write a lot about it in my Notes to keep it sticking.

Cheers, and good luck!!