Complex sentence: With the creation of GHQAF it was further de-emphasized and the 9th was converted into a bombardment group and made a part of the 2nd Wing, responsible for the air defense of the East Coast of the United States.
Split into simpler sentences: With the creation of GHQAF it was further de-emphasized and the 9th was converted into a bombardment group. Made a part of the 2nd Wing, the 9th BG was responsible for the air defense of the East Coast of the United States.