Isaiah is part of the biblical canon for Catholics. The Greek used there in the Septuagint is κακά--which is a generic word meaning "bad things." The Vulgate translates it as "malum," also meaning "a bad thing." More telling are the words used in juxtaposition. The Septuagint provides us with "ειρήνην," meaning "peace," but in the sense of "quiet, tranquility" rather than "absence of war" or "harmony" (for which concepts Greek has other words). The Latin "pacem" has a broader meaning than ειρήνη but it definitely encompasses the same idea. I understand that Latin is not a primary Biblical language, but Jerome knew his Greek well, so it's telling that he chose malum.

When we say "God doesn't create evil," it is moral evil being referred to specifically. Given that Isaiah is reporting a series of spoken opposites and antonyms, the κακά being referred to is most likely to signify something more like "bad disturbances," think storms, earthquakes, etc.

Obviously this is just one line of analysis on a complicated passage, but I felt it important to point out that the oldest manuscript we have for the passage does not say something like "malice, villainy, moral evil," which the generic English translation of "evil" does not really bring out.