If they still live with their parents, apparently not.
I think I see fuggles' point. Savannah is earning money but not technically supporting herself (supposedly, as I have not clue what that family dynamic is, and suspect he doesn't either). But that distinction is irrelevant. If your job pays you money, then you can claim that job title. And she probably does better, financially, than a good amount of players who would actually fit his definition of pro.
Everyone here knows who she is. This thread, which I started, was about Sofia and it's become about Savannah. Savannah's been in mainstream media, she has a social media following, she has always had sponsorships in excess of her playing ability, all as a result of having always done well getting publicity. Many players could take notes, as I would hazard a guess that Savannah's sponsorship haul is top-5 amongst US players. And not just the women, all players.
To not call her a pro because she doesn't pay rent or a mortgage is silly, to me, but there's that saying, "we'll have to agree to disagree."