When to start upgrading to TH9 level defense?

Been TH9 for a month or two, all offense buildings done and some war troops researched. I've brought all my new defenses to max TH8 level, started working on legos(15 done), and my heroes are only 10/6.

Should I keep defenses at a lower level while I upgrade walls + heroes, or start upgrading them to TH9 level? Builders are running nonstop, and I don't want defense going ahead of my offense. Also, in what order should I upgrade the defenses?

Sounds like your doing good, I would just keep your builders busy if that means upgrading your defenses to Th9 levels then so be it. I'd do splash defenses first to TH9 level.

i hope you already have your xbows. those are crucial. i started upgrading my defenses immediately, they take quite some time.

Lvl1 Xbows are essentially pointless, don't worry about them if u haven't built them, and if u have keep them lvl 1 for war, because they add A LOT of weight. Do wizard towers first, then mortars, then air defenses, then teslas

Walls are important but definitely not more than defenses

I suggest that you start elixir upgrades and when you finish them start doing defenses and you will find that you farm a lot of elixir more than your needs so, use them to upgrade your walls and you will find that you have finished a big amount of walls when you finish your defenses.

I'm in a similar situation. Starting to upgrade my war troops right now, and I'm slowly doing air defences, mortars, xbows and wizard towers, one at a time. So far, war is doing good right now and my offense is looking good.

I recommend maxing all your traps (not teslas) to buy time for more war troops upgrades.

Personally, I maxed xbows before other defenses but by the time I got my lvl 4 golems (got lvl 6 loons and lvl 5 hogs b4 that). I maxed cannons next. Then mortars. Now I'm doing teslas and ads and wiz. Lastly archers

For reference. Maxed war troops (except valks still lvl 2) 1 day ago. I have lvl 3 xbows, all lvl 11 cannons, 2 lvl 7 ads, all lvl 7 mortars, 1lvl 7 ad and 2 lvl 7 teslas on the way. About 160 legos. Rest skulls. Heroes 10/11.

So you're doing it right haha. I've kept 4 builders going constantly with the 5th for walls. You can do you drills or your de storage etc if u wanna slow down on defenses which I do recommend. Also I have had no problems in war matchups with this method.