The generator matrix

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

generates a code of length 9 over Z9 who´s minimum homogenous weight is 18.

Homogenous weight enumerator: w(x)=1x^0+78x^18+2x^27

The gray image is a code over GF(3) with n=27, k=4 and d=18.
This code was found by Heurico 1.16 in 0.000186 seconds.