Actually libflashsupport does not fully fix the problems Flash9 has with PA.
The libflashsupport interfacing in Flash9 is racy. Thus you might get a freeze or crash in some cases when you close a web site in your browser. All people that had a look on this problem agree that we cannot really work around this in our code -- it is Adobe's job to fix this. And you know what? Adobe actually did so, in Flash 10.
So, in summary: Flash 9 on PA is not perfectly stable, regardless how you run it. But the people to blame for that are not us, it's Adobe. Please point your fingers in the right direction when you complain!
(Running Flash 9 in libflashsupport in a plugin wrapper is the best way to run Flash on PA right now. That way crashing flash will not bring your entire browser down -- and if you ask me, allowing closed source software to run inside the browser process is a bad idea anyway.)