No 2 people are likely to get the same results as everyone has different configurations and use different apps in different ways but yeah, it's doable. The least time I got on a change was 6 hours and that was transferring a ton of stuff across my local network and several restarts for app installs.
Yeah I hear you on that, different things are going to yield different results.
I do tend to have pretty "routine" usage of my devices though, and I understand what it's capable of and what it's not. If it's possible to get ~9 hours out of this, then my particular usage would probably fall within that range.