SSN holder만 가능합니다. 가족 중에 한 명이라도 ITIN이 있으면 못 받는 것 같습니다.
https://crsreports.congress.gov/product/pdf/IN/IN11282
“SSN Requirement: Taxpayers would be required to provide a Social Security number (SSN) for themselves, their spouse (if married filing jointly), and any child for whom they claim the $500 child credit. Adoption taxpayer ID numbers (ATINs) are also acceptable for adopted children. Taxpayers who provide an individual taxpayer identification number (ITIN) would be ineligible for the credit. Hence, married couples in which one spouse has an SSN and another has an ITIN would generally be ineligible for the credit.”