Fountain of Knowledge

I think as long as they are hinted at and there is other conflict, it's okay. I guess it kind of depends on how long you plan on making your story as well and if you are going to have other books in the series that take up the same plot. Mostly though, I think if you bring it in at chapter nine it should be okay as long as you are keeping the reader interested with something. I don't like it when things come out of no where either, so the hinting at it would be important.