Early gender test

Kim • Married in august, pregnant in September ❤️ First time mommy and can't wait! Dental hygienist baking a little GIRL! 🤰🏼

How early is the earliest a blood test can determine the babies gender? My first OB appt is at 9 weeks and they said they'd order a blood test but I've heard it's not detectable until 10 weeks Ladies please share your stories!