The Crumble software is written in python, so unfortunately, porting it to ChromeOS looks like a lot of work. Recently, Google have announced a way of running Android apps on ChromeOS, so that might ease things a little, but I haven’t looked into it yet.
Using Scratch could be interesting. I’m assuming it’s running in the cloud? I wonder if a little ChromeOS app could enable communication from Scratch. Although, the Crumble would only work when connected to the Chromebook, so depending on your application, it might not be ideal.