The generator matrix

 1  0  0  0  0  0  1  1  1
 0  1  0  0  0  0  1  0  0
 0  0  1  0  0  0  1  0  0
 0  0  0  1  0  0  1  0  0
 0  0  0  0  1  0  1  0  0
 0  0  0  0  0  1  1  0  0
 0  0  0  0  0  0  X  0  0
 0  0  0  0  0  0  0  X  0
 0  0  0  0  0  0  0  0  X

generates a code of length 9 over Z2[X]/(X^2) who´s minimum homogenous weight is 2.

Homogenous weight enumerator: w(x)=1x^0+69x^2+792x^4+4368x^6+11154x^8+11154x^10+4368x^12+792x^14+69x^16+1x^18

The gray image is a linear code over GF(2) with n=18, k=15 and d=2.
As d=2 is an upper bound for linear (18,15,2)-codes, this code is optimal over Z2[X]/(X^2) for dimension 15.
This code was found by Heurico 1.16 in 0.795 seconds.