(b) An authorized agency shall not refer to the adoption service a child in its care who has been legally freed for adoption when the child has been placed with a foster parent who has expressed, in writing, an interest in adopting the child; provided, however, that such child shall be referred to the adoption service in accordance with paragraph (a) of this subdivision where the foster parent has withdrawn interest in adopting the child or has been disapproved as an adoptive resource for the child. An authorized agency shall not refer to the adoption service a child in its care who has been legally freed for adoption where the agency has identified two or more potential placements for the child; provided, however, that such child shall be referred to the adoption service in accordance with paragraph (a) of this subdivision when such child has not been placed into an adoptive home within nine months of having been freed for adoption.