While we are still working out exactly how to distribute the final Player version to be as easy as possible for the typical end user, this beta includes 2 gzip'd tarball packages: one is for the Mozilla plugin and the other is for a GTK-based Standalone Flash Player.
I Already installed without problems for the moment (remember is beta) check it on two sites on my country that already use Flash PLayer 9, view only one video on youtube so not idea with heavy use if it's more or less stable for debian (the same to knoppix).

More info & Download link on: Beta Is Live