Okay, ignore my previous post, I gave up on 9p. Someone on the ubuntu forums showed me a guide for mounting nfs shares in fstab, and I was able to get that working.
I have a new question now. how do I get zfs to auto publish the zfs shares on boot and on array start? My VMs seem to start up before the shares are available, which doesn't make them happy. If I enter "zfs share -a" into the unraid console and restart the VMs they all work fine.
I've tried:
using the user script addon to run "zfs share -a" on array start, but it either doesn't work, or runs too late
adding "zfs share -a" to the /boot/config/go (not 100% sure I did this correctly though)
manually adding the shares to /etc/exports, but it got overwritten the next time I restarted unraid].
I'm out of ideas, and could use some help if someone would be kind enough.