having said that in the 90s I was once on a design team that built a CPU with 8 9-bit bytes in a word and an 81-bit instruction (9 9-bit bytes). It was a DSP,

having said that in the 90s I was once on a design team that built a CPU with 8 9-bit bytes in a word and an 81-bit instruction (9 9-bit bytes). It was a DSP, memory was still relatively expensive and MPEG needed 9-bit delta frames, however DRAMS with byte parity were available so it was a price point that made sense at the time