I haven't had any bug or crash issues so far (probably about 4 to 6 hours playing .9n on a new save)
I'm unfamiliar with the thing "fusion" though, and am not sure what you are referencing.
He's talking about a framework mod, more or less. Which hasn't been updated since 0.8.2, to my knowledge. So, yeah, it would obviously cause crashes because it's out of date.
Edit: I correct myself. I was thinking of Voidmod when it comes to a Framework that hasn't been updated. Fusion is fine, and I have used it fine.