I changed your topic title to generate more replies by having what you are actually asking about in the title. 😁
I don't recommend it unless absolutely necessary. If you are working on your ATV, you should raise it up. As far as if it's safe, I would disconnect the battery so you don't get any ignition starts accidentally and the other safety issue is rolling over on someone, so make sure it's well supported.
I have front and rear hard storage, so I stock it with some extra water, extra Gal of gas, Winch accessory kit w/ tow and recovery strap, a 1st Aid kit, and compressor.