WAFS and WASPS were issued Berets not soft caps with bills. Looks like a Driver uniform to me.
If enlisted in Army..NARA online database of enlistments 1939-1946http://aad.archives.gov/aad/series-list.jsp?cat=WR26
Ancestry has Navy Muster rolls and crew lists. With his name you maybe able to look up when he was given the First Class Machinist Mate Rate. (sleeve insignia) That way you can date the picture or closely.