/sharepoint /share 9p trans=virtio,version=9p2000.L,rw 0 0
After rebooting I got some weird errors and was forced into emergency mode. My first thought was that SELinux was causing this trouble (as mentioned in the guide) but I checked and SELinux was disabled by default in Kali Linux.
After some searching, I found this. Apparently the 9p modules needs preloading. This means adding these three lines to /etc/initramfs-tools/modules
9p 9pnet 9pnet_virtio
and then running
sudo update-initramfs -u
There are other solutions mentioned in the superuser.com question libvirt/9p/kvm mount in fstab fails to mount at boot time that I didn't try but this worked like a charm.
Depending on your level of paranoia this might perhaps pose a security risk. ↩