The reason for one of its idiosyncratic 1870s compromises between logic & technological imperative was the desire to make it easy to type dates. Hence I is just below the 8 - & so of course is the 9.
Perhaps the inventor thought that keyboards would have ceased to be in use by the time we needed the O to be just below the 2.
Links
Fry's English Delight - Series 3 - 1. The Trial of Qwerty
Radio review: Fry's English Delight: The Trial Of Qwerty
Fry's English Delight - Series 3 - 1. The Trial of Qwerty
Radio review: Fry's English Delight: The Trial Of Qwerty