That's exactly the one we've been working off of.
We currently have the MVC app set up in a virtual directory of the CMS App, in the same solution. When we started with K8, we used the MVC code in the root of the CMS app, but when we upgraded to K9, we were told by phone support that it would be better to put our MVC project in a subdirectory/virtual directory.
One thing that we did do differently was to explicitly set up the SearchService in the controller's constructor, instead of receiving one from a parameter. Is maybe that the issue?
var indexInfos = SearchIndexInfoProvider.GetSearchIndexes();
string indexNames = (from i in indexInfos
mService = new SearchService( indexNames, CultureHelper.GetDefaultCultureCode( "SCGDEV" ), "SCGDEV",true );