There wasn’t a Windows 9 because a lot of (poorly) written software will do a system check for Windows version and if the first number is “9”, it won’t work and complain that you need to be using a Windows OS newer than Windows 9x (95/98).
It was just for backwards compatibility more than anything.
All the images in the article are showing that the hand with missing fingers is the left hand. Most people are right handed, so missing a left finger for most people wouldn’t hurt the grip strength of a one handed weapon/tool much in the main (right) hand. You could attach something like a shield strapped to your left arm and wouldn’t notice the issue for hunter gathering then. (Shields aren’t just for defense against claws, they can also be a bashing tool.)
Now, I doubt they were cutting off a pinky finger because they were bored on a Saturday night, but there could have been religious/group beliefs involved. Body modification has been around for a very long time, from as simple of scarification, to tattoos and piercings, to removal of body parts (circumcision), so it isn’t out of the realm of possibilities.