Not a silly question.

I can't speak to the S9, but standard PC components (non-MILspec) are not speced for very low temperatures.  There's also the issue of any dampness on the board freezing and causing physical damage. We had to get some heating for a server exposed to a CT winter.

I think I would want to heat it the room slowly before I started it up, then check the exhaust was maintaining the correct working temperature in the space.