while none of the arguments of the article came even close to being convincing or to balancing out the disadvantages of a non-power-of-two orientation, there actually is one totally different argument/domain where the 9 bit per byte thing would hold true, that is: ECC bits in consumer devices (as opposed to just on servers):

The fact that Intel managed to push their shitty market segmentation strategy of only even supporting ECC RAM on servers has rather nefarious and long-lasting consequences.