[*] Except for the original developer/porter, of course.
I'm curious, because I've tried Plan9 a couple of times now on the Pi. It boots fine, so I'm 90% sure I did everything right in terms of writing the image to the SD card, but neither keyboard nor mouse works (so I end up having to pull the power plug to shut it down). The screen looks fine (and piques my interest!). One of the windows on the screen shows USB errors - and everytime I plug or unplug a keyboard or mouse from the USB port, messages (i.e., more errors) show up in this window. I've also tried another keyboard, but no change in results.
I assume the problem is (are) the usual USB/power issues. But note that I am using the same power/keyboard/mouse combination that I've used all along - and which works fine with the usual Linux distros and also works fine with RISCOS, so I'm reasonably sure that it (the power/keyboard/mouse combo) is reasonably good (for use with the Pi). But there is something about Plan9 that just doesn't like it.
Note: Image was downloaded from the site yesterday - so should be current.
Any suggestions of things to try? Or, as I suspect, is it just not ready for anyone other than the developers?