UB-9's commanding officer at commissioning only remained in charge of the ship for a week. Sources do not report any more commanding officers assigned through the end of the war, so it's not clear if the submarine remained in commission. UB-9 was reported in use as a training vessel at Kiel in September 1915. The U-boat made no war patrols and sank no ships during the war, which may indicate that the vessel remained in a training role. At the end of the war, UB-9 was deemed unseaworthy and unable to surrender at Harwich with the rest of Germany's U-boat fleet. She remained in Germany where she was broken up by Dräger at Lübeck in 1919.