If you have problems finding a Shimano replacement, Microshift makes compatible shifters. I've not used any of their shifters but did replace a front road der. for a 3 x 9 and have found the part well made and works fine. Link to one w/o gear indicator, but they also make one with an indicator, if you want.
Marvo Xpress Shifters 2/3x9 | microSHIFT