SSD(9, 3^7) via Theorem 4 (n=2, s=3)

0 0 0 0 0 0 0
0 1 1 1 1 1 1
0 2 2 2 2 2 2
1 0 1 2 1 2 0
1 1 2 0 2 0 1
1 2 0 1 0 1 2
2 0 2 1 1 0 2
2 1 0 2 2 1 0
2 2 1 0 0 2 1

Note: The overall A2 value is 6; the possible projected A2 values are 0 and 2/3 with frequencies 12 and 9.  
The first column is orthogonal to all other columns.