You have been told three times that a W-9 is what you need. That is the proper answer.
This is from a state of California "FAQ" about this topic (it does not involve officials, but independent contractors):
My service-providers have federal employer identification numbers (FEINs) and business names. How do I determine if they are sole proprietors? Can I report their FEINs instead of their social security numbers (SSNs)?
By statute, you are required to obtain the first name, last name, and SSN of any service-providers that are sole proprietors. The federal
Form W-9 was recently revised and now requires sole proprietors to list their first and last names. You may want your service-providers to complete new Forms W-9. If the SSN is still not known after reviewing the W-9, ask the service-provider for the SSN. If the service-provider does not provide it, fill out the SSN box with zeroes (000000000).