My site is now running on Drupal 9! The upgrade was pretty straightforward with only a few things to correct in some custom modules so they could be read and registered in Drupal 9. On deck are a half dozen client projects to bring from 8.6+ to Drupal 9.
I see people ask or state they are confused about how to deploy Drupal 8 when most (if not all) hosting platforms disallow running tools like Composer or NPM in production.