You can uninstall or removes an installed adacgi3 package itself from Debian 9 (Stretch) through the terminal,
$ sudo apt-get remove adacgi3
If you would like to remove adacgi3 and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove adacgi3
If you use with purge options to adacgi3 package all the configuration and dependent packages will be removed.
$ sudo apt-get purge adacgi3
If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.
$ sudo apt-get purge --auto-remove adacgi3