Hi ~ Can you tell me of any way to run Mac OS 10.6.8 (Snow Leopard)? on my mid-2012 MacBook Pro(9,1) that originally shipped with Mac OS 10.7, now running Mac OS 10.14.6 (Mojave)? –I would love to have a Snow Leopard partition on it...
I don´t think Snow Leo can be run on your MBP natively with passable effort.
Some Hackintosh users did run SL 10.6.8 on IvyBridge rigs using the mach kernel from (Mountain) Lion, but this was only to get OSX running at all.
Virtualisation via VMWare is working for 10.6 Server, so you might try that.
Considering Hackintosh, there are many SandyBridge laptops for sale that will run Snow Leo with the help of Nawcoms Mod - CD or USB.
10.6.8 won't install by default under VMWare Fusion (which is now free for personal use), but it will install under VirtualBox. However, 10.6.8 Server will install under VMWare Fusion, and 10.6.8 just needs /System/Library/CoreServices/ServerVersion.plist to exist for VMWare Fusion to boot (you can create your installation in VBox, add the file [I duplicate SystemVersion.plist] and then create a new VM in VMWare using the vhd from VBox). Then just remove the file and take a snapshot. If you reboot, you'll need to add the file back for the system to boot back up in VMWare.
As far as I know the last macbooks to run Snow Leopard where the late 2011 ones. I bought one specifically for that. It seems the 2012 onwards had a piece of firmware blocking installation. Back in the day I read there were some rather painful workarounds. It worked downgrading the firmware, but it could cause issues with some hardware. I have no idea how to do that and I am not sure which firmware people were targetting exactly.. my memory on the subject is vague at best.
I reckon using some hackintosh techniques may be helpful.