Why do I need my babysitters ssn and address? It’s asking for this info to verify child care credit. She was a teenager I paid to come to my house but is no longer with us.

The IRS wants that information to be able to check if the sitter is paying tax on that income, assuming that the sitter has a filing requirement. 

If you do not have this info and or do not wish to get the info then you cannot take the credit.