To uninstall debian-security-support just follow these instructions.
/debian/stretch/main///install/index.html Debian security support coverage checker Debian 9.0 admin 2017.06.02
sudo apt-get remove debian-security-support
Which will remove just the debian-security-support package itself.
sudo apt-get remove --auto-remove debian-security-support
This will remove the debian-security-support package and any other dependant packages which are no longer needed.
If you also want to delete your local/config files for debian-security-support then this will work.
sudo apt-get purge debian-security-support
Or similarly, like this debian-security-support
sudo apt-get purge --auto-remove debian-security-support
|Description||Debian security support coverage checker|