Should I upgrade to Town Hall 9 Yet?

I'm currently a Town Hall 8 with all of my structures and regular elixir troops maxed (my Barb King is level 10, and all of my barracks and teslas are maxed out).

At the moment, what still needs to be maxed is:
Minions (Upgrading to Level 3)
Hog Riders (Level 1)
Valkyries (Level 1)
Golems (Level 1)
Level 8 Walls (51/225)

I'd like to max out my Minions, Hogs, and Golems but the upgrade times for maxing out all of those would take about 47 days, assuming I do them all continuously, and I'm not sure if it's worth wasting that much time with all of my builders open when I could be doing Town Hall 9 upgrades instead. I know I could finish the walls in about 2-3 weeks, and I don't know if it would be better to hold off the lab upgrades for Town Hall 9 because there are much fewer regular elixir upgrades at Town Hall 8.

Personally, I was considering farming walls for another week or so, then upgrade my Town Hall around December 9th so that it will be done when my winter break starts, so that is probably the earliest I would start the upgrade.

So, at the point at which I am, would it be a waste to stay at TH8 with all of my builders open for over a month, or should I upgrade to TH9 as soon as I can and disregard what little I have left to upgrade?

I'd say you're golden, upgrade around December 9th as you said. Get minions to lvl 4 while you wait to upgrade, and farm walls until it's done but make sure you have max storages when your th9 completes. Don't worry about the other DE troops tbh, you'll be able to get DE a lot faster at TH9 with your stronger troop levels.

Yes, you are ready. I would advise knocking out your walls too in the next couple weeks before your upgrade finishes like you said. It's easily doable now. I'm sure you know how to farm by now, but BAM in C3 is how I finished out my walls at TH8.

As always, max your storages and have 60k+ DE on hand to get that queen to lvl 2 in 12 hours. She's going to make you love this game soooooo much better!