4.5 weeks & 9,021 HCG?

Hi! My OB estimated my peanut at 4.5-5 weeks based on my LMP & U/S - no heartbeat yet but the fetal pole & yolk sac were seen. They took blood & called to let me know my HCG was 9,021 and my progesterone was 11.6.. he suggested oral progesterone to be on the safe side.. my question is, for 4.5-5 weeks, 9021 HCG seems on the high side, no? The ranges I’ve googled are a few hundred to 5,000+.. could it mean twins and they just didn’t see the second? The U/S tech was a fill in and unfamiliar with their equipment. He said he wanted to do another U/S next week “to see how things are progressing”.