Here's the classification:
Divisible by 5 and 9: 90
Divisible by 6 and 9: None
Divisible by 2 and 6: 72, 84, 96
So the numbers 54, 72, 84, 90, and 96 can be placed into the following boxes:
More than 1 box: 72, 84, 96
Divisible by 5 and 9: 90
Divisible by 6 and 9: None
Divisible by 2 and 6: 72, 84, 96