Do you think GNU Emacs users would be interested in using 9P protocol from within the editor, implying an Emacs Lisp 9P Client/Server might be authored?
The 9p.scm (client) hyperlink in the above URL is dead, and it has a new home at the below URL.
Maybe other GNU Emacs users have another opinion to that of R. Stallman's (circa 2017) response which is reproduced below.
"It makes no sense to put this feature into Emacs, which is the wrong place for it. The right place for it is in the kernel (Linux or the Hurd), so that all the application programs will be able to use it."