No, he confirmed that he'd heard the same rumor. If he'd said, "Yes, that's the case" or "Yes, that's true" - those would count as confirmations.
"Yeah, I heard that too" means nothing. If Alaska Darin posts that Chin-Mang Wong (from the Yankees) might be out for the year and I reply "Yeah, I heard that too", that's not a confirmation. It's me saying a heard the same thing.
Cooper also said that he had other sources but refused to disclose them to Tim Russert on the air. Probably because they were other reporters. Probably because her identity wasn't much of a secret, which of course is the main issue.