The generator matrix

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

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+23x^8+64x^9+96x^10+64x^11+16x^12+64x^13+96x^14+64x^15+23x^16+1x^24

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 1.10 in 0 seconds.