The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1
 0  X  0  0  0  X  X  X a*X a^3*X  0  X a*X a^6*X  0 a^3*X 2*X  X
 0  0  X  0  0 a^7*X a^6*X a*X 2*X a^7*X  X a^7*X a*X a^2*X a^7*X  0 a^2*X a^7*X
 0  0  0  X  0 a^7*X  X a^2*X a^2*X a^6*X a^3*X a^6*X a^3*X a^5*X a^3*X a*X  0 a^5*X
 0  0  0  0  X a^6*X 2*X a^3*X  X  X a*X a*X  X a^2*X a^7*X a*X a*X a^7*X

generates a code of length 18 over F9[X]/(X^2) who´s minimum homogenous weight is 108.

Homogenous weight enumerator: w(x)=1x^0+552x^108+2384x^117+4928x^126+10688x^135+490024x^144+15808x^153+7056x^162

The gray image is a linear code over GF(9) with n=162, k=6 and d=108.
This code was found by Heurico 1.16 in 18.9 seconds.