Answer: The unaccompanied homeless youth status is not a professional judgement decision. Financial aid administrators are required to make a determination of UHY status based on the legal definition of homelessness. See DCL ID: GEN-15-16 from the US Department of Education.
Also, per the 2018-19 FSA Handbook, page AVG-117, “If a student does not have and cannot get documentation from any of the authorities given on page 27, you (the financial aid administrator) must determine if she is an unaccompanied youth who is homeless or is self- supporting and at risk of being homeless.”