“This may fit on line 9, but line 12b also has a nine.”
Yes, but, the federal stats don’t apply to box 12b, so there is no way for us to know what that 9 meant in that box. It’s foolish to claim that a 9 meant, “Unknown or not stated”, when that meaning was not used until seven years later, in a different field.
Yet a code was required and there is no code for a blank entry. 9 may have been the bastard code by default.