If she’s only there a couple of days, she’s trying to best organize her time. She may have had a longer date offered at the same time tonight- she didn’t cancel on you, she asked if it was ok. Tomorrow, she may have had her 6pm ask to extend (if she’s doing 1 hour appointments), or she may have realized she didn’t leave a long enough break to go for dinner.

It’s the opposite of sketchy. A shady provider would disappear, a sting wouldn’t keep changing your “booking” time.

If you can make it at 9, that helps her make more money and/or have a better break. It would be the nice and generous thing to do. If you can’t, you can’t.