I'd go to the junkyard, and find calipers from 10 inch rotors.
Next, measure the distance between bolts that hold them to the hub carrier.
Next, measure the spacing from the 10 inch junkyard discs back to where the caliper mounts.
If distance between bolts is the same; and distance from caliper to disc is the same, see if the brake line/hose threads are the same. If all measurements match, probably you will have found an easy bolt-on,
..........*IF* the piston diameter and volume of fluid behind the piston is the same as you have with your current 9" discs. Otherwise, either pedal effort may increase, or there won't be enough brake fluid volume to activate the calipers.
.........It might be less effort to work overtime to earn the money and actually buy the brembo calipers for your particular car.................Keep us posted on what you find that works.-Bob