From what I have seen it depends more on level than age, levels 1/2 probably 3-4 hours level 3 6-9 hours though my kiddo did 12 at level 3 but it may have been a bit much I think they have lowered the hours a bit for level 3/4 at our gym. Mine was 7/8 years old at level 3 for reference.
Yes... it has much more to do with level / ability than age. With an average 5-6 year old... there is only so much that you can do. If your 5-6 year old is more like a Level 4 with Level 7 abilities like a cast handstand on bars... then there is much more that can be done. Honestly though... we don't really push hours on that age group much anymore... we would start higher hours with ages 7-8.
Mine is 7 in a group of 5-7 yo girls and they do 6 hours/week. It’s an efficient, fast-paced 6 hours and a small group. I don’t see them standing or waiting unless it’s for 20 seconds of instructions. They powerwalk to water breaks, so more hours in their situation would be too much.
Depends on the level most 6 year olds at our gym are level 1/2 so there for 6/9 hours. One 6 year old is a level 3 so there 12 hours I believe. One 7 year old in our level was level 4 last year but training with optionals so she was doing 19 hours at 6. Her mom works at the gym so she’s there all the time anyway