D:\>perl -lne "print /^[0-8]{9}$/ && !/(.)(?=.*\1)/ ? 'ok' : 'not ok'"
1234
not ok
1234567689
not ok
012345678
ok
018273645
ok
010101010
not ok
^Z

##</code><code>##

D:\>perl -lne "print /^(?:([0-8])(?!.*\1)){9}$/ ? 'ok' : 'not ok'"
123456780
ok
123123123
not ok
123456781
not ok
^Z