1970 Topps checklist #9 is a bit of a puzzle, as there are two distinct versions, but it's more complex than that. I usually refer to the separate variations as: top of bat reaches the white border and; top of bat ends short of the white border. This could usually be explained as a simple registration problem regarding the colors mixed to make the brown bat or, more likely, the layer of red. However, that certainly doesn't fully explain it and I call your attention to the portion of the card I've highlighted in this gif.
If you look between the batter's elbow and his midsection, you'll see a black line there. In the one version, it's at the lowest point of the batter graphic and appears to 'close' the yellow box. But in the other version, this line is significantly higher up (and on a bit of a downward slant) and no longer connected to the very bottom of the batter. Since both the batter and this line are part of the black printing plate, the layout had to have been changed at some point, making this a true variation.
To play devil's advocate, I will say there's a tiny possibility that this line is actually part of the red/magenta plate, so it's movement would fit in with the obvious shift of that color. However, under strong magnification, I see nothing but a black/grey line there, so I'm not sure that's a reasonable counter-argument.