Is that 9 days idling? That's fantastic for a nexus 5! Mine is running stock Android, it's over 2 years old, and the battery lasts maybe 16 hours with normal daily usage. It's still a very capable phone, but it's a shame it's becoming unsupported and slowing down as makes their apps more sluggish. I switched to an iPhone SE recently, Google's apps run much better on iOS in my opinion.