After installing the List Print on your SharePoint farm, you will need to activate the Bamboo List Print Site Collection feature before you can use it on any site of the collection.
As part of the installation process, you may have automatically deployed List Print to one or more web applications on your farm, but it is not possible to automatically activate a feature on individual Site Collections in the web application (check this).
For List Print, there is just one Site Collection feature to activate at the Site Collection level. There are no Site Features.
Do I need to activate this feature? If you do not activate this feature, you will not see the Print List option on the List Ribbon (or the Actions… menu if using WSSv3/MOSS) on any list or library in sites of the site collection.