I think you have come to the right place, finally!.
There are many hearsay out there, many are ignorant to the powerful Placebo and expectation bias effects that virtually no one is immune to.
If you are happy with using the pre outs of the 5010 with you Emotiva amp then I would just keep using it until you are really ready for 9.1.6. By that time, more bugs would have been fixed.., or more bug free devices would be available for you to choose from.
For 9.1.6, unless Denon offers one by the time you are ready, you would have no choice but to go with an expensive AV preamp processor. Currently the best measured Denon AVR-X8500H and the A110 can only do up to 7.1.6. You can connect 15 speakers so that you can flip between Atmos and and Auro 3D but it cannot process 15 channels simultaneously.
If you are fine with just 13 channel processing then currently the AVR-X8500H measured better than any separate processors, it beats even the $15,000 Storm Audio. So I would suggest you ignore those You-tube videos, especially the one in which the two gents said they found even a AV7705 (might have been 7706) sounded better (in terms of channel separation, sound stage etc. blablablabla) than even the more expensive SR8015 (that measured much better). They obviously have no idea what's inside those gear, it was the most hilarious HT video I have seen.
Those two guys seem to think any any separates (so called) would beat any AVR. I hope that's not the one you viewed.
One more thing, those guys typically would use the popular arguments that its your ears, stupid, not specs and measurements.., sounds convincing for sure.