Just collected my pair from my retailer, the build quality of these is simply incredible, extremely well put together. My earlier concern regarding the circular earcups turns out to be unfounded, maybe I have small ears but my ears fit in the cups nicely and the pads are very comfortable. I don't find volume to be a problem either - music gets sufficiently loud at 50-60% on my iPhone 7. To be honest, I didn't have much expectation with regards to bluetooth headphones(this is my first), but this exceeded my expectations and then some, it has a very engaging sound signature, suppose it will be easy to get lost in music when travelling. Maybe it is the new toy syndrome talking but I think it is good enough for me that I am considering to use them at home as well. If nothing, being able to walk around the house while still being connected to my home library is a big plus by itself.
I tried the Sony 1000x for a bit while I was there, and it really doesn't compare(sound quality, comfort, and especially build quality), but I do think that ANC on the Sony is (alot) better but I find the H9's to be "good enough", it also has a noticeably less "vacuum feeling" on my ears compared to the Sony making them far more comfortable to me overall. But then my priority is sound quality then ANC, if ANC is your first priority then the 1000x should be given more consideration.
Edit: I find it incredible that B&O didn't include a hard case for these, it would have been a perfect package if they throw in a hard case for travellers. Now I have to use the given cloth pouch until my hard case arrive, shame.