This penny the 9 in the date has been struck over an 8. I have posted two pictures. This is as clear as the 1944 D over S penny.
There is no 9 or 8 Overdate strike Lincoln Cent... Looks like some kind of corrosion on your Cent D over S can occur because Mint Marks are added by hand to the Obverse Die. Those are called RPM's - Repunched Mint Marks.. Never the numerals on the Date.
Notice how the looks of the 9 changed between the two images. There is something on the coin that is moving around. It's not an overdate.