I'm really not sure what makes this a fun trope but I'm biased and not the authority on what's fun. In my experience, though, the only time blindness gets to seem fun is when a character has super awesome other senses to the point that they're as or even more capable than sighted people like Daredevil and, it's seeming, Kanan.
If that's what a player is after, then there's no reason to make special rules for it. Just have them behave like sighted people and attribute their Mountain Dew fetching proficiency to other senses. Other than the comic relief aspect of it ("Wait. SHE'S DRIVING???") or some fun with Advantages ("He had hotdogs for lunch... yesterday."), be done with it.
In that case, as for seemingly impossible feats like ship piloting, it's up to the player to make it happen. Normally, I would have no argument with the ruling that says a blind person simply can't drive. However, in the shared fantasy of a Star Wars game, anything might go. But no one should assume special treatment. That would be unfair to everyone not getting such treatment. The GM can apply penalties, as necessary and the player can buy the skills and Talents to compensate.
Verisimilitude can be preserved by attributing his unexplainable abilities to the will of the Force. We don't know that Chirrut Imwe was anything but a believer in the Force but it surely seemed to help when his actions were what seemed to be in line with the will of the Force. Considering how open he was about those beliefs, if he actually showed any true talent, it seems logical to guess the Empire would have picked him up at some point.
If he's not asking to make an advantage out of blindness, what's the harm?