Once you have your ESMC setup, they still have 6.6.866.1 in the repository. You'll have the option to install 6.6.866.1 or 6.7.500.0... just use the older 6.6.866.1.
I have many clients that I manage via ESMC on OS X 10.13.6 having kernel panics as well. ESET Endpoint Security 6.7.500 and Agent version 7.0.432.
Please fix this quickly, ESET!!