It would be interesting to see if this works out on going from a FreeBSD host to a Windows guest.
From what I remember for when I did some research before on Window's implementation of Plan 9, including some more recent research; it did indicate there may be some issues in it. From what it looks like, when MS implemented 9P for WSL; they did it all with very narrow blinders on. If anyone is a little interested in a little of MS's 9P implementation; this link (from 2020) goes into detail of how it was implemented. https://www.mcafee.com/blogs/other-blogs/mcafee-labs/hunting-for-blues-the-wsl-plan-9-protocol-bsod/
From what I remember for when I did some research before on Window's implementation of Plan 9, including some more recent research; it did indicate there may be some issues in it. From what it looks like, when MS implemented 9P for WSL; they did it all with very narrow blinders on. If anyone is a little interested in a little of MS's 9P implementation; this link (from 2020) goes into detail of how it was implemented. https://www.mcafee.com/blogs/other-blogs/mcafee-labs/hunting-for-blues-the-wsl-plan-9-protocol-bsod/