How about if your 9 year old soon-to-be nikyu is in the same dojo as his older sister, mom and dad? My kids are one rank above us. I'm sure it helps that the wife and I are kohei. Most times his stances are sloppy. Sometimes his kata is ragged. Nevertheless, he almost always shows spirt, intensity and focus when executing. His technique might be wanting but he tries. He seems to enjoy being there and that is what is important. During the kids class in our dojo the serious stuff has some fun and games is interspersed with it. Remember that play is an important part of learning grown up tasks. Like in kata there are hidden messages in some of games we play. OP, just remember your son is only 9. He might not be able to perfectly translate what he sees and what he knows into what he does. If he's not enjoying himself at all then try finding out why. The pressure to grade may be a bit much on him. You should talk to your sensei privately about the situation. It's tough coaching 3rd graders and even tougher when the athlete is your own kid. Remember at 9 they think they know everything.