A county board may provide for the establishment or maintenance, or may enter into contractual agreements with other counties, townships or municipalities for the establishment or maintenance of youth service bureaus, or may enter into contractual agreements with established youth service bureaus, public or private, serving the general area of the county. Such agreements shall be written and shall provide for services to residents of the county under 18 years of age, but agencies providing such services to adults in addition to youths may qualify as youth service bureaus. “Youth service bureau” means any public or private agency providing, or arranging for the provision of, assistance to persons referred to such bureau by law enforcement officials, court agencies and other agencies and individuals with the intention of diverting such persons from formal processes of the court. However, this Section shall not be construed to amend, modify or have any effect on the Juvenile Court Act of 1987, as amended. For the purposes of this Section, the county board is authorized to expend moneys not appropriated for other purposes, including funds made available from the federal “State and Local Fiscal Assistance Act of 1972”. This Section shall not constitute a limitation on or a prohibition of the exercise of powers of a home rule county.