Hi, I live in earthquake prone Northern California. I don't think you can retrofit the wall, there's too many things you'd need to do. Just stuffing rebar down the holes and filling them with concrete may make the wall stronger, but what's the foundation underneath? I was within 5 miles of the epicenter of Loma Prieta quake in '89 and I remember a bunch of cinderblock walls coming down in the quake. I'd remove it and rebuild it with sufficient footings under some sufficient vertical support.
Oh wait, idea. You could possibly bolt some 3-4" dia pipes to it every
6 feet or so. This is just a guess. Every 6 feet, dig a 2 foot hole, put the pipe in, run long bolts thru the pipe, thru the cinderblock, into a big steel washer/plate on the other side. Probably use about 4 bolts along the length of the pipe. Then fill the hole with concrete.
Realistically, since I don't think there's an easy fix for this, and since you are probably right that, after a quake, it may come down. If you're going to put some sweat into this job, get a civil engineer to take a look at it and give you some good advice. It would cost you a modest amount, but at least you'd know you were doing the right thing. Otherwise, you may do a bunch of 'work' to make it good in your own sight, but the thing would still come down. Look what happened to the Cypress structure in Oakland during Loma Prieta, and that even had engineers design it. Bottom line, engineers know quite a bit more now than they did then and that knowledge will help you out in this situation.