When editing a page, are you using the Block editor, or the Classic editor plugin?
If using the Classic editor, I have 5.9 installed, and when editing a page with the classic editor plugin, I can see the “text color” tool in the editor toolbar. You do have to click the “toolbar Toggle” tool to expand the toolbar to two lines of tools.
If you don’t see it there, then try deactivating ALL non weaver plugins to see if that solve it.
If you are using the block editor, you need to explain what text color button you are speaking of.