Hello all FM server admins.
I have discovered a workaround for the problem of administering a FM server running on OS X for versions 9 and newer due to the recent update of Java.
Because versions 9 and newer have the ability to be administered remotely, access the OS X based FM server from a web browser running on a Microsoft Windows machine, if you have one handy.
You will need to uninstall the newest version of the Java RTE (deselecting it with the java control panel is not good enough) from the Windows machine. Once done, point your favourite web browser at http://yourFMserver:16000/ and you should get the login screen to your FM server. I think you need to be logged into the Windows machine with administrative privileges to get this all to work.
It's working just fine for me. It should work for you.