Tricky.
Here's an old thread with lots of Kentucky discussion. Seems like KY might be one of the hardest (or least friendly) states to get 'er done.
https://www.skoolie.net/forums/f6/hello-from-southern-kentucky-16730.html and this one:
https://www.skoolie.net/forums/f18/pre-conversion-and-unregistered-in-ky-that-simple-38257.html
I did a quick check of KY DMV regs and you might be able to have the local sheriff's office do an inspection and identify it as a Bus, if the current title information is not that.
Here's a little clip from the Fayette county clerk's website (
https://fayettecountyclerk.com/web/vehicles/moreoptions/regtypes.htm):
'Non-commercial vehicles are used for personal use regardless of make, model or size. These vehicles are primarily designed for carrying passengers and having provisions for not more than nine (9) passengers, including the operator. Pickup trucks, SUV's and passenger vans will receive a standard issue license plate.'
I don't see requirements for converting to a motor home or RV like there are in other states, but I would at least pull the seats out so you can meet the above requirement.
Maybe: you might be able to use the application for title or registration to 'fix' your registration with an inspection from the local Sheriff (who would need to sign off on the form):
https://transportation.ky.gov/Organizational-Resources/Forms/TC 96-182.pdf
From my read, I'd mark 'other' for type of application, make sure the body style is bus and be prepared to provide a certified weight from any commercial truck scale that gives the actual bus weight.
You will not be able to get a 10,000 lb plate because buses and shuttle buses all are over that weight.
The vehicle clearly will not be a commercial vehicle, and that's a good thing because typically registration costs for commercial vehicles are based on weight. Also, insurance becomes problematic if the vehicle is commercial and not personal in the system.
I also found a local facebook group for Kentucky Skoolies here:
https://www.facebook.com/groups/1028386937620609/
Finally there's another couple who converted their bus in Kentucky and are active on Instagram-'thesouthernskoolie'. Check them out, and maybe reach out to see how they did their registration.
It's challenging, but nothing that dogged determinism and time can't fix.
Good luck, and let us know how things go.