The following is a tabular presentation of the topological ordering algorithm 
trace from the Topo Ordering notes (using depth-first traversal):

Start at:  0

Pass 1:  0, 5, 1, 7
     2:  3, 4, 8, 2
     3:  6
     4:  9
     
Solution:  9, 6, 3, 4, 8, 2, 0, 5, 1, 7