Wondering anyone else encountered issues with SAT registration for kids younger than 10 years old?

DC's SAT application got returned due to "Date of birth is missing or invalid" even though the birthday was entered correctly. When we contacted College Board, 9 out of 10 representatives stated there is no minimum age requirement, but one person stated kids younger than 10yo cannot take the SAT. Is this true? Is this a new rule?

Any BTDT or advice on SAT registration for younger kids? If testing through a talent search program, which one do you recommend? (Duke TIP program said the child has to be in the 7th grade to take the SAT through them.)

Thanks!