The generator matrix

 1  0  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  0  1  1  1  1  1  0  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  3  1  1  1  1  1  3  1  1 6a+3  1  1  1  1  1  1 3a  1  1  1 6a+3  1  1  1  1  1  1  1 3a+3  1  1 6a+3  1  1  1  1  1  1 6a+3  1  1  1  1  1  1  1
 0  1  1  a 7a+7 8a+4 3a+5 8a+5 8a a+5  0 a+5 8a  a 8a+5 3a+7 7a+7 8a+4  1 3a+5  0 3a+7 8a+5 8a+4  1  a 2a+5 3a+5  3 3a 8a 6a+5 7a+7 a+5  0 3a+7 8a+3 8a+7 a+8 8a+7 3a+3 8a+1 4a+5 a+7  1 a+3 6a+5 a+3 6a+1 a+7  1 8a+3 a+2  1 2a 2a+5  3 4a 8a+3 8a+8  1 7a+8  7 2a+5  1 2a+6 4a+7 4a 5a+2 6a+2 6a+7 6a+7  1 2a+4 5a+8  1 a+7  2 5a+4 a+8 3a+1 3a+8  1 4a+4 2a+5 7a+5 2a+8 a+3  3  0
 0  0 3a+6  0 3a+6  3 6a+6 6a+6  6 3a 3a+6 3a  3  0 6a 6a+3 6a+6  6 6a 3a 6a  6 3a 6a+3 6a 3a+3 6a 3a+6 6a 3a  6  3  0 3a+6 3a 3a+3  0 6a+3 3a  6  6 3a+3  3  6 3a  0 3a  3 3a+6 6a 3a+3  6 3a+3 3a 6a  3 3a+6 3a+3 3a 3a+3 6a 6a+3 6a+3 6a+6 6a+6  0 3a+6  6 3a+6  6  3  0  3  3 6a  6 6a  0 3a  3 6a 6a 3a  0  6  0  3  3 6a+3 3a
 0  0  0  3 3a+6 3a+6  3 3a  3 3a+3 6a 6a+6 6a 3a 3a+3 3a+6  0 6a+3 3a 6a+3 6a+6  6 3a 6a  3  0  6  3 3a  6 6a+6 6a+3 3a+6  6 6a+3 3a+6  3  6  3 6a+6 6a+3 6a+3  6 3a+6 3a 6a+3 6a+6  3  6  0 6a 3a+3 3a  0 6a 6a+6 3a 6a 3a+3 6a+6 3a+3 3a+3 6a 6a  0  0  0 3a+3 6a  6 6a+3 3a+3  6 6a+6  0 6a+6 3a 3a+3 6a 3a 3a+3 6a+6 3a+6 6a+6  0 3a+6 3a+3 3a  0 3a

generates a code of length 90 over GR(81,9) who´s minimum homogenous weight is 684.

Homogenous weight enumerator: w(x)=1x^0+280x^684+72x^685+792x^692+1880x^693+792x^694+2880x^695+15912x^701+8944x^702+4176x^703+10512x^704+38232x^710+19104x^711+11160x^712+22464x^713+105912x^719+42640x^720+19944x^721+40320x^722+101592x^728+36912x^729+16344x^730+28800x^731+480x^738+360x^747+328x^756+296x^765+184x^774+48x^783+72x^792+8x^801

The gray image is a code over GF(9) with n=810, k=6 and d=684.
This code was found by Heurico 1.16 in 53.7 seconds.