it'd be all in ones viewpoint and imagination, look ,see, just whats going on down around the lower end of the grip and go from there, won't need any "heavy equipment" to lop off and a "smooth"??? maybe "melt"?? a little off here and there....hhhmmm
...see below, guess there is a hammer spring down there,, oh oh an "impasse".
Welcome to the forum! I think it's possible, but because the hammer spring is anchored near the bottom of the grip, you would likely need a shorter hammer spring, plus an arrangement to anchor the short spring inside the shortened grip. As mentioned above, it might be easier to just buy a new or used Security-9 Compact (although the barrel would be shorter than proposal).
If you don't already have one, consider getting the compact model. The Ruger "compact" will accept the full size magazines. And, I believe that Ruger makes/sells a spacer to fill the void and makes the extended mag part of the grip. If possible, verify this BEFORE purchase. Fwiw.