The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  X  X  1  1  1  1  X
 0  X 2X  0 X+3 2X 2X+6  6 X+3 X+3  0 2X  0 X+3 X+3 2X  3  X 2X 2X+6 X+3
 0  0  6  0  0  0  3  0  3  3  6  3  0  6  6  0  6  0  6  3  3
 0  0  0  6  0  6  3  3  3  3  3  0  0  0  3  6  6  3  0  0  3
 0  0  0  0  3  3  6  0  3  6  3  3  3  0  3  3  0  3  3  0  0

generates a code of length 21 over Z9[X]/(X^2+3,3X) who´s minimum homogenous weight is 36.

Homogenous weight enumerator: w(x)=1x^0+306x^36+162x^38+390x^39+486x^40+648x^41+2142x^42+972x^43+648x^44+648x^45+132x^48+26x^54

The gray image is a code over GF(3) with n=189, k=8 and d=108.
This code was found by Heurico 1.16 in 40.4 seconds.