Actually RM8 has been at for year and a half now. Many programs do yearly releases. As for learnign how to do everything again, no, because what you are used to now, it is about 99% the same in RM9. RM9 is just RM8 with some new features.
As for support, RM has pretty much alway provided support for their previous releases until people move on to newer ones. If you post here, or on Facebook or somewhere to ask questions, make sure you specify what version you are using. Now as for updates, those usually stop with the release of a new version, so it is not likely that you will see further updates, but questions about RM8 will continue to be answered.