[FBinNY]

Consider doing it in steps.

First use your experience and determine the chainring size that will give you the gear range you'll need. If you rarely use the outer with the smaller cassette cogs, you can afford to shrink it a bit, or try riding with only the middle ring for a while and decide if it's too big, too small or just about right.

If the middle chainring is about the right size, consider going to a 1x9 by simply removing the outer and granny rings and FD. Using the middle ring on triple cranks usually yields a decent chainline. You'll need shorter chainring bolts which cost $5.00-10.00 for the set. Or you can leave the outer on, possibly after filling the teeth down a bit, as a bash guard, and use the original c/r bolt set. You can also replace the chainring with a larger or smaller one leaving the rest as is.

So far you've spent little or no money to try out 1x9. If you like it, you have time to research your crankset oprions and budget, or consider staying as is, maybe replacing only the chainring, and buying a proper bashguard.