Here's some history on the unit. As you said, the typist should have stated 39th Infantry Regiment. I will have to write to them.
9th Infantry Div - 39th Inf Reg
The Division was reactivated August 1st, 1940 at Ft Bragg, North Carolina as a precautionary measure in preparation of World War II with the following units:
39th Infantry Regiment (From the 4th Division)
47th Infantry Regiment (From the 4th Division)
60th Infantry Regiment (From the 5th Division)
9th Division Artillery
26th Field Artillery Battalion
34th Field Artillery Battalion
60th Field Artillery Battalion
84th Field Artillery Battalion
9th Division Band
9th Medical Battalion
9th Quartermaster Battalion
9th Signal Battalion
9th Reconnaissance Troop
Headquarters & 9th Military Police Company
15th Engineer Battalion
709th Ordnance Company
After two years of intensive training the 9th Division was combat read by the fall of 1942 and was redesignated the 9th Infantry Division. The division was divided into three Regimental Combat Teams (RCTs); the 39th RCT, 47th RCT and 60th RCT.
The division saw a lot of combat in Northern Africa and Europe during the war. It was after the divisions performance during the Battle of the Bulge that it was nicknamed "Old Reliables". After the war the division was inactivated in Germany on January 15th, 1947.
Within six months, on July 15th, 1947, the division was reactivated at Ft. Dix, New Jersey as a training division. On May 25th, 1954, the division colors were transferred to Goepengin, Germany, to replace the 28th Infantry Division which had resumed its traditional role with the Pennsylvania National Guard. In the fall of 1956 the 9th was rotated to Ft. Carson, Colorado. By December of 1957 the division had been reorganized from the Triangular type division to the new Pentomic. The three original infantry regiments were converted to Battle Groups and the 1st Battle Groups of the 5th Infantry and the 13th Infantry were added to the division. The division was again deactivated on January 31st, 1962
WWII Campaigns
Algeria-French Morocco (8 - 11 Nov 1942)
Tunisia (7 Nov 1942 - 13 May 1943)
Sicily (9 Jul - 17 Aug 1943)
Normandy (6 Jun - 24 Jul 1944)
Northern France (25 Jul - 14 Sep 1944)
Rhineland (15 Sep 1944 - 21 Mar 1945)
Ardennes-Alsace (16 Dec 1944 - 25 Jan 1945)
Central Europe (22 Mar - 11 May 1945)
Proud Daughter of Walter (Monday) Poniedzialek
540th Engineer Combat Regiment, 2833rd Bn, H&S Co, 4th Platoon
There's "No Bridge Too Far"