The generator matrix

 1  0  0  1  1  1  1  1  1 2X  1  1  1  X 2X  1  1  X  1  1  1  1  1  0  X 2X  1  1  1  1  1  0  1  1  1  1  1  1  1  1 2X  X  0  0  1  1  1  X  0  X  1  1  1 2X  1  1  1  0  X  1 2X  1  X  1  1 2X  1  1  0
 0  1  0 2X  1 2X+1  2  0 X+2  1 2X+2 2X+1 X+2  1  1 X+1  X  1  2 2X X+2 2X+2 X+2  1  1  X  X 2X+1 X+1  X 2X  1 X+1 2X+1  X  1 X+1 2X 2X+1  1  1  1  1  1  0 2X 2X+2 2X  X  0  2  2 2X+2  1 2X+1  0  X  1  1  2  0 X+2  1 X+2  2 2X 2X+2  1  1
 0  0  1 2X+1  1 2X 2X+2  2  X  1 X+2  2 X+1  X 2X+2 X+1 2X+1  1 X+2  1 2X+1  2 2X 2X+2  0  1 X+2  0 X+2 2X+2  0 X+2 2X+2 X+1  X  2 2X  X  1  0  X X+2 2X+1 X+1  1  2 2X+2  1  1  1 2X+1 X+1  0 2X 2X+2 2X 2X 2X  2  0  1  2 2X X+2  1  1 2X+1 X+2  2

generates a code of length 69 over Z3[X]/(X^2) who´s minimum homogenous weight is 135.

Homogenous weight enumerator: w(x)=1x^0+350x^135+198x^138+72x^141+66x^144+12x^147+24x^153+6x^156

The gray image is a linear code over GF(3) with n=207, k=6 and d=135.
As d=135 is an upper bound for linear (207,6,3)-codes, this code is optimal over Z3[X]/(X^2) for dimension 6.
This code was found by Heurico 1.16 in 5.64 seconds.