Thanks for taking the time to write something up. I’m not sure if we can publish it soon enough to be useful since the release is looking likely in less than a week and someone with the website access will be needed to publish anything at all. I think the way it works is the news article must be added to Pat David / rawtherapee-web · GitLab and it will automatically be published. However, I see at least one article that is not synchronized (see the macOS instructions on the 5.9 download page). Something’s not quite right here.
A few comments about what you wrote: The term “pre-release” is not officially used in the project, so “release candidate” is the preferred term. The next version after 5.10 is to be determined. At this point, I don’t see any significant changes that will require a bump in the major version. 5.11 is most likely the next release, but time will tell.