Alignment is a general descriptor, not a iron clad rule of how people must behave.Hey, reducing large groups of people to a label and saying what they'd do based upon that label... now, I may be missing something, but that seems to be a problematic path.
As we can see from the variety of answers on this thread, a PC that decides which of these 9 broad buckets best describes their PC is free to do whatever their character would do regardless of the label they applied. The label is not, and never should be, a restriction on what the PC elects to do.