The generator matrix

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

generates a code of length 18 over Z2[X]/(X^3) who´s minimum homogenous weight is 16.

Homogenous weight enumerator: w(x)=1x^0+189x^16+172x^18+108x^20+36x^22+6x^24

The gray image is a linear code over GF(2) with n=72, k=9 and d=32.
As d=32 is an upper bound for linear (72,9,2)-codes, this code is optimal over Z2[X]/(X^3) for dimension 9.
This code was found by Heurico 1.16 in 0.00606 seconds.