The generator matrix

 1  1  1  1
 0  3  0  3
 0  0  3  6

generates a code of length 4 over Z9[X]/(X^2+6,3X) who´s minimum homogenous weight is 6.

Homogenous weight enumerator: w(x)=1x^0+12x^6+216x^8+8x^9+6x^12

The gray image is a code over GF(3) with n=36, k=5 and d=18.
This code was found by Heurico 1.16 in 4.89e-005 seconds.