"All the evidence" is pretty much worthless given that none of those players was given that much of a chance to prove themselves. Kennedy played once, away at Doncaster, and by all accounts acquitted himself well. Who knows? In a parallel universe, he and Whitehouse might have taken advantage of injuries to Collins and Doyle and are now mainstays in a title chasing Sheffield United side.
You seem to be of the opinion that the youth players have to prove that they're better than the senior pros. My opinion is that they should only show that they're not worse. Personally, I think Whitehouse might have been better than Robson and Kennedy would probably have been better than Higginbotham. Unfortunately, we'll never know.
That said, Clough does seem to rate Kennedy as despite having Hill on the bench (whose best position is centre half), he's still naming young Terry as a substitute. Same goes for Whitehouse, who has been in the squad for the past few league games.
Ironside has been given ample opportunity and has shown that he's not good enough (hence why he's now playing at Conference North level), McFadzean has well-documented off the pitch issues (remarkably similar to his older brother) and Barry has been shipped back to Ireland. There must be a reason that the other two are still around.
