The generator matrix

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

generates a code of length 20 over F9[X]/(X^2) who´s minimum homogenous weight is 126.

Homogenous weight enumerator: w(x)=1x^0+1160x^126+3184x^135+6160x^144+11520x^153+472392x^160+17560x^162+14000x^171+5464x^180

The gray image is a linear code over GF(9) with n=180, k=6 and d=126.
This code was found by Heurico 1.16 in 21.9 seconds.