I'm in the process of doing a similar thing. I'm converting an old road bike that had a 6 speed freewheel and double crankset to a 9 speed freehub cassette with a triple crankset. I would suggest looking at Microshift groups. Microshift manufactures low cost brifters and derailluers that work with 9 speed triples. Here is what I purchased for my drive train:

MicroShift R9 Dual Control Shift/Brake Levers - 3 x 9 Speed:



MicroShift FD-R539 Triple Front Derailleur - 9 Speed:



MicroShift RD-R47 Rear Derailleur - 9 Speed:



Sram PG-950 9 Speed Cassette 11-28t:



Sugino XD600 Crankset 26-36-46:



Shimano UN55 Bottom Bracket English 68 x 118mm:



I still have all the parts sitting in boxes, so I can't say yet how well everything works together. I'm waiting for my frame to be shipped back to me from the powder coater. Microshift seems to be the only company that still manufactures 9 speed and 8 speed groups with STI levers..

Another option is to use bar end friction shifters. With friction shifters, you can mix and match derailleurs, cranksets, and cassettes pretty much however you like. My touring bike has bar end shifters, an 11-34t 9-speed cassette, Shimano Deore mountain rear derailleur, and a Shimano Sora road front derailleur.