I'm reading this as using the VM for software compatibility (Linux software on Plan 9). You absolutely can do that without a VM (see: WSL1, FreeBSD/NetBSD/illum

I'm reading this as using the VM for software compatibility (Linux software on Plan 9). You absolutely can do that without a VM (see: WSL1, FreeBSD/NetBSD/illumos Linux ABI compat layers, WINE, darling, vx9, ...) but it's hard - there's a reason MS eventually created WSL2. Using a VM doesn't have very much overhead these days and gives you ~perfect compatibility with minimal effort.