ABC Apps' - "Sound Meter" - I've been using it since my Note 7 and it does everything I need - measures dB from minute to very loud sounds (as in the air horn on my truck) - it has on screen graphs, etc., can keep your screen lit while in use if you'd like! Nice app!
I measured my Air Horns at 15' in front of my F-350 and got 97 dB - that's about what I expected (or hoped I was below anyway) so I can't really answer your question. I'm sure if I put the phone on the front bumper, it would have to got well above 100 dB because the four trumpets are right behind my grille! I just never tried it!
I tried to use my Galaxy S4 to measure live music. It should have been about 114 dB. Even tho the app showed it could go higher than that, the S4 stopped at 99 dB.
I just have to find something that I know it's over 100 dB, to see what the Note 9 will do.