It's so much nicer with the fork coming out of the bottom of the head tube.

Amazing look to it. Yes, the RD will handle 9sp just fine. Either version of Tiagras will work fine and look good.
The first gen Tiagras are conducive to sanding and painting of the top caps, perhaps in yellow or dark grey to match the tricolor stuff.

Outstanding wheels. You will roll away from lots of modern wheels on downhills.