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