The generator matrix

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

generates a code of length 72 over Z9[X]/(X^2+3,3X) who´s minimum homogenous weight is 141.

Homogenous weight enumerator: w(x)=1x^0+36x^141+672x^144+18x^150+2x^216

The gray image is a code over GF(3) with n=648, k=6 and d=423.
This code was found by Heurico 1.16 in 0.135 seconds.