This happened somewhere out there:
Some of you may be surprised to learn that "annoyance" is in fact a valid legal objection. See Fed. R. Civ. P. 26(c)(1) (authorizing court to issue protective order to prevent "annoyance, embarrassment, oppression, or undue burden or expense" resulting from discovery requests). Of course, the whole system and especially discovery is annoying to start with, so something would have to be pretty frickin' annoying to justify making this objection all by itself.
I haven't seen Request No. 9 itself, so I can't say whether it was just annoying or annoying as a matter of law.