Simple approach:
D:\>perl -lne "print /^[0-8]{9}$/ && !/(.)(?=.*\1)/ ? 'ok' : 'not ok'"

[download]

This is short and very clever, but "simple"? I think NOT.
Also, I didn't see in the OP spec that this was an exact sequence of 9 digits.

In reply to Re^2: RegEx Question by Marshall
in thread RegEx Question by yoda54

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