The generator matrix

 1  0  0  1  1  1  X  1  1  1  1  X
 0  1  0  1  0  1  1  0  X  1  1  0
 0  0  1  1  1  0  1  X  X X+1  1  X
 0  0  0  X  0  0  X  0  0  X  0  X
 0  0  0  0  X  0  X  X  0  0  X  0
 0  0  0  0  0  X  X  X  X  X  X  0

generates a code of length 12 over Z2[X]/(X^2) who´s minimum homogenous weight is 8.

Homogenous weight enumerator: w(x)=1x^0+64x^8+120x^10+142x^12+128x^14+47x^16+8x^18+2x^20

The gray image is a linear code over GF(2) with n=24, k=9 and d=8.
As d=8 is an upper bound for linear (24,9,2)-codes, this code is optimal over Z2[X]/(X^2) for dimension 9.
This code was found by Heurico 1.16 in 1.05e-007 seconds.