The generator matrix

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

generates a code of length 18 over F9[X]/(X^2) who´s minimum homogenous weight is 137.

Homogenous weight enumerator: w(x)=1x^0+1296x^137+720x^144+4536x^146+8x^162

The gray image is a linear code over GF(9) with n=162, k=4 and d=137.
This code was found by Heurico 1.16 in 0.00179 seconds.