Running Start9 (EmbassyOS / StartOS) can be done directly on hardware or in a VM. Which is best for you depends on your specific needs and desires.
I've run Start9 OS on a VM for testing purposes to let me snapshot, try things, blow it away and restart. My actual servers running my nodes and services are all physical hardware.
In general if you are running your servers long term I'd suggest running them directly to get best performance and least issues. If you are experimenting and may need to 'roll back' changes frequently then a Virtual Machine can be handy.
Your mileage may vary.
#grownostr #start9 #virtualmachine #homeserver