Hi, No, they aren’t interchangeable. Only “He turned out to be married” is correct. The other one is grammatically incorrect.

I corrected them. It turned out he's married. He turned out to be married.

It turned out he's married. It turned out he was married.

As Profe José demonstrates 'it turned out . .' and 'he turned out . .' are used in different contexts. They are both statements of what later became evident; however 'He turned out . . ' refers to the character or activity of a particular person, while 'It turned out . . ' does not necessarily do this, and could refer to a situation in general.

He turned out to be a very nice guy. He turned out to be a very mean fellow.