I have been teaching kids since the early 70's and have worked with many kids with "special needs" as well. Over the years, I have learned to treat kids like adults with the same expectations. If you treat them like adults they begin to act like adults and think like adults and learn to take responsibility. With much younger kids, I emphasize more flexibility and hand-eye, hand-foot coordination exercises, balance, footwork are important. Many kids do not receive enough strength training as well in the public school system, some running, jogging in place, push-ups and sit-ups are also important.
Kids must be quiet, learn to bow and say, Hai!, when spoken to in my Dojo. They must keep their uniforms clean and behave themselves. Many of my kids continue and graduate to the adult classes and some have become black belts in turn. One of my assistants started when he was fourteen. One student who started with me in college is still with me for the last 35 years. Several of my kids, I have seen recently are now married with kids of their own.
Kids need respect and if given respect, will in turn learn to respect others. They must learn that it is all give and take. If I act silly in class to entertain them, they will act silly too. If you act seriously in class, they will become more serious about what they are doing.
Kids need honesty, and do not like to be cheated, feel cheated or lied to. You must be very alert when teaching kids because they absorb everything you do and say. Finally, all kids have a natural genius and it is up to you to help them to develop their genius and natural talents.
I have not ever met any bad kids, but I have met a lot who have "learned" to be bad. Sometimes we have to correct this too and Aikido is the very best for this.
If you have a good heart, the kids will sense this and develop their good hearts too. I recommend all my black belts to help out with our children's class to develop their teaching skills. Some people can teach adults but not kids. If you can teach kids well, you can teach anyone very well. A kids will challenge you as a teacher - you will learn more from teaching the kids than they will ever learn from you. Give them all you have. Hope these hints help you out. Thanks.