Any park district has the power subject to the limitations of Sections 9.3-1 through 9.3-6 to acquire, construct and operate such revenue producing recreation facilities and to extend or improve such facilities, borrow money and as evidence thereof to issue its bonds, payable solely from the revenue derived from the operation of such recreation facility or facilities. These bonds may be issued in such amounts as may be necessary to provide sufficient funds to pay all costs of acquisition or construction, or extension or improvement of indoor or outdoor recreation facilities, including engineering, legal and other expenses, together with interest on the bonds to a date six months subsequent to the estimated date of completion. The bonds are negotiable instruments and shall be executed by the President and Secretary of the district and countersigned by the Treasurer.