My child is a minor and received a SSA 1099. How do I determine if I need to file that on my taxes?

You do not enter a dependent's Social Security benefits on your tax return.  If the child has no other income they do not report the SS benefits received on a tax return.

You don't include their income on your return. It would only go on their return if they are required to file one.  If they only get ssi or SS, SSDI or a SSA-1099 they don't have to file a return and nobody reports it. And it doesn’t affect you from claiming him.  

Do I report my dependent’s SSA-1099 on my return?

https://ttlc.intuit.com/turbotax-support/en-us/help-article/taxation/need-report-dependent-ssa-1099-return/L3hjHQLWL_US_en_US

Filing requirements for a dependent

https://ttlc.intuit.com/community/children-dependents/help/do-i-need-to-file-my-own-taxes-if-i-m-a-dependent/00/26111