I would say that at face value all of these sentences refer to a time before his graduation. Technically, it's true that the are ambiguous, but I think that most speakers would resolve the ambiguity for themselves by assuming they meant before, if there were no other context to make their meaning clear.
Of course, these sentences wouldn't be without context, and the context is where we would derive more understanding of their intended meaning.
It was six months from his graduation from college. He was glad it was over.
It was six months from his graduation from college. He was filled with anticipation of the ceremony.
The sentences that use 'away from' are more clearly referencing the period before than the ones without 'away'. I can't think of any context where this usage would mean after.
Without the word 'away' it is less clear whether the meaning is before or after.
We would normally use 'after' instead of 'from' to indicate the period after he graduated.
It was six months after his graduation from college.