I sure wouldn't recommend building up a 9 speed bike, now that Campy has mostly forgotten about it with 10 speed fading fast and 11 speed getting all of the development.

9 speed shifters can be converted to 10 speed fairly cheap, but the lowest priced 10 speed shifters are so cheap, it's hardly worth doing the conversion. New Veloce shifters are only about $120 and that includes a new cable set worth about $50.

Depending on the model year of the shifters, they may only work best with RDs older than 2001. In 2001 Campy changed the RD actuation ratio slightly. Older shifters only work perfectly with the older RDs.

Forget about trying to mix other brands of RDs. It won't work.