TH 8.75 is a compromise between the mainstream 8.5 theory and normal TH 9 bases. Going with the theory that base design (as opposed to defense level) is the single most important defense that a TH 9 has.
The general theory is to bring the defenses (except walls) up to max TH 8 levels (over time) while not upgrading anything beyond that (X-bows are to remain at lvl 1).
Once defenses are max TH 8, you can use gold to upgrade walls, elixir to upgrade troops, spells and/or dark barracks and dark elixir to upgrade royals and/or dark troops.
Special note: Jump is very useful to TH 9 strategies, essentially saving spell slots (from having to earthquake) and upgrading jump to lvl 2 doubles the time. While it is lvl 1, you should practice using it but upgrading it becomes a priority.
This gives the advantage of having full attack capabilities and adds the lowest weight for war match-making (walls). Walls are also great for defense, adding hit points to every defense, in essence. Mass wall upgrades are the only real way to do this.
After your walls are max for TH 9, supposedly, there are defenses that hold less war match-making weight. These include all traps (teslas would be a priority here), wizard towers, mortars and cannons. Archer towers and air defenses, supposedly, hold the most weight.
Of course, anytime you are being attacked by the same army types and re-working your base does not change it, you can upgrade defenses to help defend it. These may be ground point damage (teslas, skeleton traps, giant bombs, cannons and archer towers) against hogs, air point damage (teslas, skeleton traps, air bombs, air mines, archer towers and air defenses) against air attacks, etc.
General Upgrade StrategyEdit
Suggested upgrades for a new TH 9:
GOLD: The most expensive thing is the CC upgrade so do this right away, if you have the money. The next goal should be one of the new X-bows then a new tesla. Since there is not enough gold to get everything, buy the new items that do not require builder time and work your way up the time expense and down the gold expense. For instance, buying the AT, storages, walls, air mines and GB will not cost time while buying the X-bow, Tesla and Air sweeper will cost money. Work down the money side and up the time side.
ELIXIR: Start the spell factory upgrade right away. After that, switch between upgrading dark barracks and dark elixir collectors. You can throw in dark spell factory whenever, since it is not a requirement to war but while down you need to opt out of wars. Less important but can be a pain is your dark barracks, if you can get these up as far as possible before you war, it is nice to be able to make armies without having one down.
DARK ELIXIR: Only one thing, Archer Queen leveled up as much as possible. After that, troop upgrades and normal leveling (see below).
Since everything is very expensive at TH 9, upgrading troop levels to bring more attack capability to war is problematic. While we WANT to upgrade troop levels, the reality is that it is going to take a long time.
Upgrading what you farm with (healers, minions and AQ if you use queen walks to pick on TH 8's) becomes a priority. Upgrading the AQ in general is one of the best things for both farming and war as well. Getting the AQ to a certain level (10, 15, etc.) allows less of other troops to be needed in farming and war.
Also, upgrading your DE collectors becomes a priority (above and beyond troop upgrades) because the long term benefit of DE production will help with all DE war troops. Protecting DE collectors is paramount since they will give plenty of DE to attackers as well.
When going for troop upgrades for war, the priority becomes golems because most attacks use golems. In order to use laloon, max loons are needed although bases more commonly defend against that now, you can't laloon without max loons but you can laloon with only lvl 1 hounds. Upgrading hogs will give more leeway to GoHo, which is the easiest and most common strat used for starting TH 9's. Upgrading Witches to lvl 2 will give GoWiWi a much better chance to 3 star, especially with a Queen walk for the opposite side of the base.