Fostering Stable Housing Opportunities Act of 2017 This bill amends the United States Housing Act of 1937 to include within the definition of "families" a child who is in foster care and has attained an age such that the provision of foster care for such child will end by reason of the age of the child within six months. Preference is given, subject to certain terms and conditions, for public housing occupancy and section 8 housing assistance under such Act to certain otherwise eligible children who are aging out of foster care and are at-risk for homelessness. The bill amends the Housing Act of 1949 to give preference for rural rental assistance to certain otherwise eligible children who are aging out of foster care and are at-risk of homelessness.