The loot penalty is significant. It is easier to raid TH9 and TH8 when you are a TH9 than it is to raid TH10 and TH9 when you are TH10. This simple fact means that unless you suddenly find a way to farm TH10/9 bases as quickly as you can farm TH9/8, then your loot is going to drop - even if loot is available!
Now, add to this the fact that there is a reduction of available loot and ou have a nasty ♥♥♥♥tail that leaves you with a nasty headache after 1hr of straight playing...probably equating to mostly pressing next. If I boost my troops and play solid for an hour, I literally do not see enough high yielding raids to net me what I was casually making at TH9, no boost and healthy amounts of clan chat...simples.
I say upgrade OP. You clearly want to. So that makes it the best thing for you...

