perl, 106 bytes

Result

AC

Duration

486ms

Code [DL]

@z=glob`dd`;$A+=(@z[$_]-=@z[$_+3])*($_>5&&@z[++$_%3+3]*@z[++$_%3]-@z[$_%3+3]*@z[--$_%3])for 0..8;print$A/6

stdin

09 12 98
14 20 61
05 56 09
68 14 54

stdout

7357

stderr

0+1 records in
0+1 records out

strace