The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  X  1  1  1  1  1  1  1  1  1  X  1
 0  X  0  0  X  X a*X a^3*X  0 2*X a^2*X  X a^2*X a*X a^2*X a^5*X a*X a^6*X a^2*X a^3*X a*X a^3*X a^6*X a^5*X  0 a^5*X  0 2*X 2*X  X  X 2*X a*X  0 a^7*X a^5*X 2*X a*X  0 a^2*X a^2*X a^5*X a^2*X a^6*X a^5*X 2*X a^3*X a^2*X 2*X a^6*X 2*X  X a^3*X a^7*X a^2*X a*X a^2*X a^6*X 2*X a^3*X a^3*X  0 a^6*X a^3*X a^6*X a^5*X a^6*X a^3*X  0 a^2*X 2*X  0  X  X a^2*X a^5*X a*X a*X  0 a^3*X  X a*X  X  0
 0  0  X  0 a^7*X a^6*X a*X 2*X  X a^6*X a^6*X  X a^3*X  X a^5*X  X a^2*X  0 a^7*X a^7*X a^6*X a*X a^3*X a*X a^3*X a^3*X a*X 2*X a^3*X a^5*X a^7*X 2*X a^2*X a*X  X  X a^6*X  0 a^2*X 2*X  X a*X a^7*X a*X a^3*X a^7*X  0 a^3*X a^7*X 2*X a^3*X  0 a^5*X 2*X 2*X  X a^3*X a^7*X  0 2*X a*X 2*X a*X a*X a^5*X  0 a^5*X  0 a^7*X a^5*X a^7*X a^3*X a^6*X a^7*X 2*X a^3*X 2*X  0 a^5*X a^7*X a^5*X a^6*X  0  0
 0  0  0  X a^7*X  X a^5*X a*X a*X a^7*X 2*X a^7*X a^3*X a^2*X 2*X a^3*X a^6*X a^6*X  0 2*X a^7*X a^7*X  X  X a^6*X 2*X a*X a^7*X  X a*X a^5*X 2*X 2*X  X a^6*X a*X  X a^7*X a^6*X a^7*X a^6*X a^3*X a*X a*X a^7*X  0  X a^2*X 2*X  0 a^3*X  X a^7*X a*X a^5*X a*X a^6*X a^5*X a^7*X 2*X a^5*X a^6*X a^2*X a^6*X a^3*X 2*X 2*X a^6*X 2*X  X a^3*X a^3*X a^5*X a*X  0 a*X  0  0 a*X a^5*X 2*X a^6*X a^2*X a*X

generates a code of length 84 over F9[X]/(X^2) who´s minimum homogenous weight is 639.

Homogenous weight enumerator: w(x)=1x^0+448x^639+1272x^648+648x^656+984x^657+10368x^665+1024x^666+41472x^674+672x^675+488x^684+544x^693+352x^702+352x^711+216x^720+112x^729+72x^738+24x^747

The gray image is a linear code over GF(9) with n=756, k=5 and d=639.
This code was found by Heurico 1.16 in 1.85 seconds.