azza, yours is a mtn crankset and likes to be paired with mtn or bar end shifters and mtn FD which is designed for shifting on 47-50mm mtn chainlines. STIs won't work well with mtn FDs, so you need to use a road FD which are designed for shifting narrower road chainlines ~45mm. You can swap one of the 2.5mm plastic BB spacers from the DS to NDS to reduce the chainline from 50mm to 47.5mm and try using a 9s road triple FD with your STIs. It may work, but I think shifting to the large chainring would not be good. A trekking crankset which uses a square taper BB would be easier to match with road FD and STIs because you can use a BB with correct spindle length to bring the chainline all the way in to ~45mm. With your Hollowtech mtn crankset you can only reduce it to 47.5mm. Also, STIs will work with some models of 9s mtn RDs but not others, so you may have that to ponder as well.