Hogs are the strongest attack true for Town Hall 8. When using hogs, the first thing you must worried about are the clan castle troops. If you do not kill the clan castle troops, even one will destroy all of your hogs. Second, you must figure out where the giant bombs are. Giant bombs will do a lot of damage to your hogs, but a double set of giant bombs, (i.e. when 2 are next to each other) will wipe them out.
When Giants bombs are on the outer portion of the base, they are very easy to manage. One can send in a few hogs to trip them. But, when they are in the center of the base, they become a more of a problem.
There are several ways to deal with this problem. One can use golems, wizards, and hogs. Most people use one or two golems, up to 10 Wizards, wallbreakers if needed, and the rest hogs. As with every other attack, you must kill the clan castle troops before releasing hogs. One can use the Golem and wizards to do so, often with a rage spell. With the new clan castle that allows one to bring a dark spell, one can bring a poison spell in the clan castle and a poison spell of their own. Level one spells will not be enough. One should bring level 2 spells or a level one and a level 3. The key is with this attack, is to get the golems to trigger the giant bombs. One could use this strategy to trigger giant bombs that are not in the center, but there are easier ways to do so–i.e. with hogs. The GoHo is an extremely effective attack at both TH8 and TH9 that most should become familiar with if they want to 3 star bases.
Alternatively, one could use Surgical hogs to go in and trigger at least one of the giant bombs in the center of the base. This requires careful planning and one must know the path at the hogs will take to ensure that they will get there. It is most important to trigger at least one of the bombs that are next to another bomb (a giant double bomb set). See the attached video to see how this works. It is essential to master surgical hog attacks if you want to 3 star TH9s. Studying hog pathing is essential.
Another method is to use surgical hogs. They can be used to take out certain defenses, such as air defenses, when using hogs with dragons. This is not a commonly seen attack, but it is very effective. See the attached video as a demonstration. One could use other troops instead of dragons as a clean up troop, such as wizards. Essentially, with surgical hogs one must ensure that a large mass of hogs do not run across double Giant bomb sets.
3 star hog attacks using 4 dragons and hogs