Serves me right for commenting when I was away from my measurements. But this might surprise you.
- The P1 peak is marginally smaller - but its there. It occurs around 12-13 kHz which is why it won't bug a lot of people. I do know one person who it affects quite a bit, and he has issues with it.
- P1 also has more bass which will mask the upper treble. F9Pro has less so likely to manifest more peak if you are sensitive to that frequency
- F9 Pro (as per my review) will give some people issues with the 8 kHz spike. But not everyone gets those issues - and it depends on your sensitivity to certain frequencies (which is what i was trying to say - albeit badly)
In short - both have a peak, although for the majority of people, the P1's peak is less likely to be problematic. And its generally a good idea not to assume that just because you have an issue at a certain frequency, so will everyone else. You'll notice in my comment that I stated "I don’t find them accentuating sibilance".
Anyway - graph here so you can see.