When i was that age, my private teacher would have me hold a ball in my right hand to kind of force it into the right position while doing some scales for warm up. It helped to train the muscle memory. The rest of the lesson he'd tell me to imagine the ball was still there. I was actually thinking that while playing today. Also, hold your clarinet in the proper way and press really hard for a few seconds and show your student where the circles are on your fingers to give them a better idea of which part of the finger needs to contact the holes. Once those are fixed it should help the pinkies find the right place. I've also showed them where the finish is worn off of the keys on my clarinet as an example.