The generator matrix

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

generates a code of length 7 over Z3[X]/(X^2) who´s minimum homogenous weight is 9.

Homogenous weight enumerator: w(x)=1x^0+52x^9+162x^10+234x^12+648x^13+342x^15+648x^16+100x^18

The gray image is a linear code over GF(3) with n=21, k=7 and d=9.
This code was found by Heurico 1.13 in 0.000844 seconds.