He did tell Cat. He also told the Kents that Kal-El (the baby from the spaceship) was the last son of Krypton. So, he told them about his planet too.
So they do know Krypton is no more. Hmm.
They don’t know about the time-travel though.
I was going with, they can tell Clark is x age. I am not sure they really could deduce his age, but if they could, they would assume he was born in 1962 or so.
