You may be referring to the 14th Tank Battalion, 9th Armored Division, 3d Army but it's hard to say for certain. "Brown Service Star" probably indicates "bronze service star." This is a small device worn on the ribbon of the appropriate campaign or service medal (in this case, the European- African-Middle Eastern Theater Medal or EAMET - quite possibly the "RAMAT" you refer to. From the other info given, this probably represents participation in the Northern France Campaign (25 July to 14 September 1944). The battalion is credited with three campaigns but your Dad may not have taken part in all three for a variety of reasons. "NCO 631 Intell" (space number 30 on the WD AGO Form 53-55) indicates he was an "Intelligence Non-Commissioned Officer", his military occupational specialty (MOS). The number, 631, is the standard indentifying number for that particular MOS at that time. I can provide just about any type of information you're seeking. If there's any cost involved I pass it along. Fair enough?
Also, it's unlikely - but not entirely impossible - that your Dad was assigned to the OSS. They were rarely, if ever, directly involved in tactical operations. He would most likely have been assigned to the Battalion S-2 (Intelligence) and would have been involved mainly in gathering and/or processing information on which routine, immediate tactical decisions were based. In any case, CIA wouldn't have that information.