yeah, I'm running a 9 speed triple on a 3x8 hybrid with trigger indexed shifting, didn't even hardly have to readjust the front derailleur (which is an awful cheap C50 sub-Tourney, eventually will get replaced with something nicer).

now, when I ran a compact double meant for a 2x10 on a 2x8 configuration, I had to put chainring spacer under the small ring. that bike was friction shift so I just had to get enough space in, I didn't have to be precise about SiS spacing, I think I used 1mm spacers.