Samuel,
Have you installed the plugin and run into issues? We just started testing 2.9, but face-to-face didn't throw up any immediate errors for us. I won't have time to fully test it until next week though.
If you are going by the listed supported versions in the plugin database, that just means that they maintainer hasn't tested it against 2.9 and hasn't updated the listing with a flag that lists 2.9 as a supported version. It doesn't necessarily mean that the module won't work.