With the extra info, it doesn't sound like you need to rush out and buy 9th grade instructional materials. Instead, since you're homeschooling, I would think about compacting (pretesting, then skipping blocks if mastery is shown) as much as possible with whatever curriculum you're using, giving bigger doses of more advanced spelling and vocab, etc. and just let him progress. I'd also make sure that his reading contains some material he finds challenging.

Striving to increase my rate of flow, and fight forum gloopiness. sick