The generator matrix

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

generates a code of length 12 over Z2[X]/(X^3) who´s minimum homogenous weight is 10.

Homogenous weight enumerator: w(x)=1x^0+150x^10+220x^12+132x^14+3x^16+6x^18

The gray image is a linear code over GF(2) with n=48, k=9 and d=20.
As d=20 is an upper bound for linear (48,9,2)-codes, this code is optimal over Z2[X]/(X^3) for dimension 9.
This code was found by Heurico 1.16 in 0.0885 seconds.