There are 2 repositories under 9p2000 topic.
Tic-Tac-Toe game expressed as a filesystem in Limbo. Shows off styx(2) and styxservers(2).
9P2000 protocol implemented in zig
Low-level, minimal implementation of Styx protocol (9P protocol from Plan 9/Inferno)
Plan9 File System in User Space for Linux
NFS-Ganesha is an NFSv3,v4,v4.1 fileserver that runs in user mode on most UNIX/Linux systems