My daughter is 9, but she would not work with this horse without her instructor/trainer. She takes 2 lessons a week, and rides once a week with her 4-H club. Age aside, she rides much better than most kids 5 years older than her. The horse she is leasing was a beginner horse, and with her instructor, has taught him his leads, side passing, pivots, etc. She is young, but she has a gift. She has handled her horse through an awful lot of issues, because her horse had not been away from the farm for 13 years when she started showing him. She is bragged about by her instructor being the youngest person on the farm to be able to know when she's got the correct lead, and being able to ask for it consistently on her horse. Until last year, when he went into a lope, he took whatever lead he felt, but she has worked hard on teaching him how to take the right lead.
My daughter has ridden about 15 different horses, from school master type, to the horse that jumps straight into the air when he sees something new. Since we work (as a family) at this farm, she has moved every horse on the propery from stall to pasture, for beginner lessons, etc. She has had them in her hands in their best and worst, and she takes it all in stride.
So, to answer your question, she's handled all levels of horses, but always under supervision of a trainer/instructor. The same would be the case if this horse were hers. The good thing about my daughter is that knows her limits, but isn't scared to push them with help. I don't want to buy her a horse that she will outgrow in skill, but I don't want to buy her a horse that is too much. I'm going back and forth on this, but am waiting for word from our instructor/trainer/barn owner to help me with my final decision. Since she knows the horse and my daughter very well, I trust her judgement on this situation.