All the children and all the adults sit together, so suppose on one side there sits 4 children, on the other sides sits 4 adults.
Suppose one of the children is Johnny.
We must always rotate the table so that Johnny is at the bottom of any orientation.
Therefore, the children must always be the bottom of the table, in the orientation.
The children have 4! ways and the adults have 4! ways.
Therefore, there are 576 ways to be seated.