The generator matrix

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

generates a code of length 46 over Z3[X]/(X^2) who´s minimum homogenous weight is 90.

Homogenous weight enumerator: w(x)=1x^0+576x^90+132x^99+20x^108

The gray image is a linear code over GF(3) with n=138, k=6 and d=90.
As d=90 is an upper bound for linear (138,6,3)-codes, this code is optimal over Z3[X]/(X^2) for dimension 6.
This code was found by Heurico 1.16 in 10 seconds.