Well, the 6809 was basically the same in these respects.

Internal registers are 16 bit, with the accumulator (A) being provisioned as two 8 bit registers (A, B) as needed. Index X, Y, Stack, User Stack, PC, are all 16 bit registers.

The Hitachi 6309, adds to that with up to 32 bit register sizes in specific cases.

In any case, the ALU and data transfers are 8 bits and I am not sure I ever saw the 6809 referenced as a 16 bit device.

Maybe 16 bit curious, LMAO.

I'd say that it's a somewhat extended 8bit device because it's still 8bit focused architecture (6800) with extensions towards better handling of 16bit values and certain common parts involved including the zero/direct page are also effectively an increase in flexibility for 8bit code not so much move to 16bit.

That said, "16bit curious" is a great term :D