You can use Kendo on a WebForm. Webforms result in an HTML page in the browser and have the structure of an HTML page in the markup, so you can use Kendo tools there as if you would on a normal .htm/.html page. Note that you should usually add custom scripts after the ScriptManager.
You cannot convert a UI for ASP.NET AJAX project to an MVC project because they are built on top of two completely different paradigms (webforms and MVC respectively). Thus, the tools from the AJAX toolset cannot work in an MVC project. You can read more about this here: http://www.telerik.com/help/aspnet-ajax/mvc-integration-with-telerik-ui-for-aspnet-ajax.html
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