The procedure you are referring is 120.4 Commodity Jurisdiction. Yes you can self designate, but you had better be correct! It is easier to simply request the DDTC to provide a "CJ" in writing for the defense article in question. The DDTC takes into account the number, variety and predominance...
AS9100 requires compliance with applicable regulatory and statutory requirements. ITAR (22 C.F.R.Chapter I, Subchapter M Parts 120-130) is a regulation covering either the manufacturing, exporting of defense articles or providing a defense service of articles listed on the United States...