Is there a way to know if your site is banned from being indexed?

yes there is a way of knowing that your site is banned. if you think your site brought up a 404 page indicating that your site is banned.

Replying to the title of your post, no there isn't.

We don't list unavailable websites and we temporarily delist those showing 404 errors. If a site comes back to life within a reasonable time, we list it again.