Which is why I said Bunshin, not Kage Bunshin. I've provided solid proof as to why Itachi would be able to create more than one Bunshin, I don't get why you're still denying it. Kakashi's chakra reserves have been said to be shite multiple times, and you're comparing him to Itachi?
Kakashi had Intel on the Sharingan in Part 1 and still fell to Tsukuyomi. The fact remains that Hiruzen won't be able to maintain eye contact with Itachi, which handicaps him heavily.
Orochimaru sucks in Genjutsu? He has a Databook 5 too, and the same amount of Genjetsu feats as Hiruzen. Even if he isn't completely subdued, he will be partially subdued and from there Itachi can finish him.