The University of California, Berkeley, has been authorised by Alcatel-Lucent to release all Plan 9 software previously governed by the Lucent Public License, Version 1.02 under the GNU General Public License, Version 2.
You can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License.
I never really dove too deep into Plan 9, but it has always fascinated me. I think it's time to learn more - and I suggest you do so too. It's weekend, after all, right?