This one is inverted 9 and heavy coin damage. Look like another coin was on top and pressed by something seriously heavy.
Yes, it looks like it got smashed against another coin in a vise or something like that. That appears to be post-mint damage (albeit somewhat interesting damage). I see no reason to doubt the authenticity of the coin.
PS- I don't see traces of the 9/6 overdate? The coin looks to have VG details to me. An undamaged example lists for $68 in G4 and $74 in VG per Numismedia (retail). The overdate would be $73 in G4 and $90 in VG8. But you'll have to deduct considerably from those numbers to account for the damage. I'd guesstimate it as a $30-40 coin as-is.
The title made me think it was a 6 1/2 cent coin. lol It's notvthe overdate variety. It's damaged so not worth very much. Welcome to CT.
I looked the damaged under a scope and I can read "17". Looks like it was damaged during very early 19th century.