$ cat test.txt
AB000000026JHAHKDFK
AB000000028JHKHKHKJ
AB00000003033AFSFAS
AB000000030HJHKH80J
AB000000030LOIKJUJ8
AB0000000324446KJHK
$
$ perl -ne '$c = substr ($_, 9, 2); print if $c ne $prev_c; $prev_c=$c;' test.txt
AB000000026JHAHKDFK
AB000000028JHKHKHKJ
AB00000003033AFSFAS
AB0000000324446KJHK