Editorial - Section 9.1 et al - Implementation Notes

I notice under Section 9.1 the appearance of two "Implementation note"s
that are not contained in a "Note" div/p such as found in 11.3. I would
suggest these simply be labeled as "Note" and consistently formatted as an
informative note (such as in 11.3). You can use the word "Implementation"
in the body of the note to indicate it is directed at implementers.