Do some subjunctive sentences mean the same with the sentences with the pattern " Too...for....to "?

You are correct, these all convey the same idea.

I think you may no realise the limited role that the subjuctive plays in English. Your sentences mean the same as

It's very important that he gets back home early.

It's very important for him to get home early.

The subjunctive is not needed and makes almost no difference to the meaning. If you're studying grammar, this is the last thing you need to learn.

The inverted form is correct but not complete, as Kate comments, this is looking for a consquence, in her example:

So important was it that he get back home early, that he booked a taxi for half an hour earlier than the time he would usually leave