1st thing as a th9 noob in war is troop capacity. Without it, you are simply just a th8 attacking.
once you have 220 troops, then you have a decent gowipe that will take out any th8 easily with th8 lvl golems.
What will help you with the lower th9 bases is witches. get them, and upgrade them to L2. That will be a mainstay for attacking. They even help getting 2 stars from a low th10 with L1 Infernos if played right.
Edit: Later on down the line, lavaloonion will be another option to take out higher level TH9's. It's all about the right army for the right base.
Followin up on the bolded underlined part, what is the decision tree that you use to pick the right army?
These are the questions that I ask myself:
1- Are the GB / Tesla positions obvious and spread apart? [hog]
2- Are their spots that could have Double GBs? [Hog]
3- Are key defense structures grouped together? [Hog / Valk]
4- Are AD's exposed? [Drag / Loon]
5- Are there any defensive structures outside the radius of AD? [Loon / Minion]
6- Is the TH less than 2 wall segments from exterior? [GoWiPe]
7- Is the CC lurable? [This mainly helps me decide troop composition]
8- Do AD area's overlap? [Ground attack vs Air]
9- Does the base use "Hog Rings" or other design elements to feed troops away from TH
10- What settings are multi-target defenses set at?
Can you guys add any other decision nodes that should be considered?