The generator matrix

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

generates a code of length 20 over F9[X]/(X^2) who´s minimum homogenous weight is 144.

Homogenous weight enumerator: w(x)=1x^0+1440x^144+8424x^145+3888x^146+5832x^152+22200x^153+58968x^154+15552x^155+87480x^160+46656x^161+87704x^162+160056x^163+33048x^164+72x^171+120x^180

The gray image is a linear code over GF(9) with n=180, k=6 and d=144.
This code was found by Heurico 1.16 in 6.58 seconds.