I can use wyrm to reduce the strength of something and then crypsis to break the subroutines right?

Sure. But keep this in mind: in order to interact with (= use its paid abilities on) a piece of ice, an icebreaker must have at least equal strength to the ice. So first you need to pump up Wyrm to match the piece of ice of which you want to lower the strength.

Given the cost of both Wyrm and Crypsis, it's not a great combo. As Saturnine points out, before you can lower and ICE Str you much first match it with Wyrm. Given how much it would cost to raise Wyrm to Str, then reduce to 0, it would be cheaper to just raise Crypsis to Str then break using Crypsis.

Wyrm is better used with fixed-strength breakers (such as Mimic or Yog.0) or in conjunction with Parasite/Datasucker to trash ICE faster.