Yes, but two is almost always better. And IME not just for larger rooms. My room is on the small side and I have no single space that is best. 100Hz null here, 60 Hz null there. Two (or more) subs in different locations helps smooth out the overall response.
If you do start with one, choose wisely in the sense that the make/model you choose now should be new enough in the lineup that it will still be available if/when you go to add the second one. Not that you can't integrate non-matching subs, but it's much easier to integrate two of the same.