Deism would be an entirely academic issue since, theoretically, that creator god would have no impact on anything that happens in the created world. There would be no religion dedicated to that god. If Huxley's agnosticism were opposed only to deism, his view would be academic too.

I'm not an expert on Huxley, but he seemed to be writing in very general terms about skepticism, which would apply both to deism and to theism. The question was about the quality of the evidence, which would tells us about the nature of the claim at issue.

Also, deism is an unstable position. If the creator god is a person, why would that person stay out of nature's way? Why wouldn't he intervene with miracles? If he's a person and he created living things, why wouldn't he care about them one way or the other? Why wouldn't he want to protect or to guide them? Or if he's displeased, why wouldn't he destroy them? And what could stop him from doing so?

So deism turns into theism, unless you naturalize or depersonalize the First Cause, in which case it turns into atheism. It's a halfway house, as I said.