Toggle between 5x5 and 9x9 grid

Years ago I recall the eyedropper tool had a 9x9 grid. Recently, in LR Classic, every time I used the eyedropper tool, it was a 5x5 grid. I searched in vain how to switch it to 9x9. I searched online, and it seemed on forums that it is not possible anymore. Instead, there's discussion about how the colors used depend on the zoom level yet always displaying in a 5x5 grid.

Well, it must be possible to switch to a 9x9 grid, because that's what is currently being used on my computer. I didn't do anything on purpose to switch it to 9x9, but I must have done something. What was it? If it reverts to 5x5 again, I'd like to switch it back to 9x9.