Using this set of SQL scripts, you can easily export a list of pages and templates that use web parts and widgets which are abandoned in Kentico 9, before choosing to upgrade.
Three scripts are included:
FindActivePageParts - This returns a list of all pages which use one or more of the abandoned widgets (in the page or in editable regions).
FindActiveTemplateParts - This returns a list of all active pages that use templates containing one or more of the abandoned web parts and widgets.
FindInactiveTemplateWebParts - This returns a list of all templates that contain one or more of the abandoned web parts or widgets in the template, but are not used by any pages.