I'm confused

Kakashi said that 9 out of the 27 graduates would become ninja. But based on the test, even assuming they were all given different "genin exams". How is it possible to pass only 9 of them if only one sensei is the one to make that judgement? The only thing i can see that pointing to is the whole thing being decided from the beginning. Otherwise it sounds like a complete plot hole. --Caseather (talk) 21:56, September 6, 2014 (UTC)