Not philosophical? And for starting techs, Animal Husbandry and Mysticism. Unique Unit could be...?
Based on his claimed authorship of several of the Psalms, I think Creative is more appropriate than Philosophical. I can't recall many other "great people" emerging during his reign, unlike, say, Elizabeth I of England (Shakespeare, Bacon, Raleigh, Drake, etc).
Aggressive makes sense to me; he was an accomplished warrior and united Israel, which IIRC was an accomplishment not repeated until the last century.
I'm tempted to replace one of these traits with Spiritual, but then, God ordered David to
not build a great temple in Jerusalem.
So I'm sticking with Creative and Aggressive for King David. But of course, I'm no modder, and any of them can put in any trait combination they want.
EDIT: Starting techs--Mysticism, definitely. Agriculture would give him a head start on AH and is appropriate for the "fertile crescent".
I don't know enough about the military history of the era to recommend a UU.