Yes, pages with a noindex tag will be picked up by the Onsite Optimizer. You’ll be able to make changes on the page as usual, however as the page won’t be indexed, this won’t have much bearing on your SEO.
You won’t be able to change the status of the noindex tag using the Onsite Optimizer - so even if you include a “index” in your Meta Robots Tag, it will be overwritten by the initial “noindex” tag found on the page.