The officer or agency empowered to entertain claims under sections 9 (a), 32, and 34 hereof [sections 9 (a), 32, and 34 of this Appendix] shall have power to hold such hearings as may be deemed necessary; to prescribe rules and regulations governing the form and contents of claims, the proof thereof, and all other matters related to proceedings on such claims; and in connection with such proceedings to issue subpenas, administer oaths, and examine witnesses. Such powers, and any other powers conferred upon such officer or agency by sections 9 (a), 32, and 34 hereof [said sections] may be exercised through subordinate officers designated by such officer or agency.