The generator matrix

 1  1  1  1  X  1  X X^2  0
 0 X^2  0 X^2 X^2  0  0 X^2 X^2

generates a code of length 9 over Z2[X]/(X^3) who´s minimum homogenous weight is 9.

Homogenous weight enumerator: w(x)=1x^0+10x^9+2x^10+2x^11+1x^12

The gray image is a linear code over GF(2) with n=36, k=4 and d=18.
As d=18 is an upper bound for linear (36,4,2)-codes, this code is optimal over Z2[X]/(X^3) for dimension 4.
This code was found by Heurico 1.16 in 0.00016 seconds.