Anyone know what this plant is? I am in usda zone 9b
You'll find them sold as bacopa, a trailing plant usd in many planters. It's not the real bacopa (Bacopa genus plants) but Chaenostoma cordatum (synonym Sutera cordata).
You can see a photo and read how to care for it (very easy care!) at Bacopa Plant Info: How To Grow A Bacopa Plant It's treated like an annual but actually it's a tender perennial. It might even be winter hardy in your zone 9b if it's planted in the ground (but not if it's in a planter).