Good job on it OP.
I am max defense TH9 and sitting here until legos done (~90 to go) and L20 heroes (14/15). I also want all war troops maxed (currently every troop max besides loon) before I go up...and anyone who knows Clash understands that Lab upgrades are significantly longer then defense...even if you only have 3-4 builders.
My main reason is that I know if I go to TH10 right now, the 6-8m upgrades will ruin the game for me...making me raid like mad to get stuff upgraded...just my personality. So, if it is a matter of hanging out at TH9, enjoying the max so that I enjoy clash for longer, then so be it.
The whole argument for loot penalty is dumb. There are equal TH9 collector raids as any other. BUT, one thing to remember is that at TH8, you will have TH7-9 raiding you. @TH9 you will have th9&10 and likely with good defenses @th10 you'll only have th10 raiding you on the reg.
As far as attacking, there is equal loot for all TH IMO. A good way to see if you are ready to go up in TH is check the majority of the bases you raided in your attack list. if they are equal TH# then upping wont matter (10% penalty). If they are mostly one TH lower than your current level, you might want to wait (would be 50% penalty).
