In the majority of US states the age of consent is 16 but the general marriage age is 18 so there quite a few states where you can have a child marriage without it being statutory rape.

If anyone is curious, the age of consent in the US is 18 in 11 states: Arizona, California, Delaware, Florida, Idaho, North Dakota, Oregon, Tennessee, Utah, Virginia, and Wisconsin.

It is 17 in 6: Colorado, Illinois, Louisiana, Missouri, New York, and Texas.

In the other 33, and also DC, it is 16.

It's interesting to compare to Europe. There it is:

  18 in 3 (Vatican City, Turkey, Malta)
  17 in 2 (Cypress, Ireland)
  16 in 20
  15 in 12
  14 in 14

Like the US the general marriage age is 18 in most of Europe, but several countries allow exceptions for 16-17 with parental or judicial consent.

if its not statutory rape before they get married, it doesn't suddenly become it afterwards.

and, as far as i am aware, it requires judicial approval right now. presumably, if it were a case constituting statutory rape, the marriage wouldn't be signed off.

this isn't about 9 year olds getting married to 30 year olds.

Yes, and the laws around that align with marriage laws, so it's still a confusing statement.