I do not remember this movie, I watched it too long ago. But in this context I would say Albert was shot out of a cannon at least once in his life. It doesn't mean necessarily he was a circus performer, maybe he was hiding in a cannon and inadvertently got shout out of it. Alternatively, he could have been a circus performer once upon a time. Nothing in your text either affirms or negates this.
I believe Albert was making conversation and talking in jest. The daughter has a helmet on because she is going to school presumably on her boyfriend's motorcycle. So Albert thought it appropriate to mention his first cannonball firing incident. He is being funny.
Teacher Mark