[Closed] Shimano compatibilty

I have to confess this is a 'roadie' question from a mostly MTB guy.

Just bought a cross bike for a friend and want to put the correct front mech on for him. Shimano compatibility guide has no mention of the brake/ shifter levers which are Dura Ace ST-7700-C and are Flight Deck compatible (whatever that means!).

The chainset is a 50/34 chainrings on FC R600 cranks and the rest of the setup is 9 speed.

The down tube is 31.whatever (32mm dia approx) and the frame will take a top or bottom pull mech. There isn't much room between the rear tyre and the frame at about 20mm so a mountain bike type mech will not fit.

Help?? If someone has a secondhand bit, I would be interested as I'm not sure that 9 speed is available now.