You’re correct. It’s two syllables. My wife is from the east coast and says it like “cran” or “crown” and some people here in the Midwest say it as a single syllable.

Dictionary defines the pronunciation as two though. Crayola, the brand that (essentially) invented them, uses two syllables as well per their commercials.

I say it as two syllables: cray-on.

I have never heard it pronounced any other way. Not American though (and I suppose you may not be either!).