Yes, Termidor SC is labeled for centipedes. Keep in mind that this product is labeled for outdoor use only. You will apply at a rate of 0.8 oz per gallon of water, 1 foot up and 1 foot out around the perimeter of the structure you are treating.
If your crawlspace is sealed then no you would not be able to dig a trench and apply Termidor inside the crawlspace, you would only apply it around the outside perimeter of your home.
It would be a great benefit to add a barrier spray outside using Termidor SC.
Just about any 1 gallon pump sprayer will do. We prefer the Chapin Premier 1 Gallon Pump Sprayer 21210XP because of the brass construction in the shutoff valve, wand, and nozzle. The nozzle is adjustable and using the pin stream spray would allow you to spray through a hole in the wall. All of the parts are replaceable when they wear out and when cared for properly will last for many years. You may want to look over our How To Do A Termite Treatment article to learn how you can protect the rest of your home against termites in the future.
Termidor SC can kill sugar ants when used outside around the perimeter of the home but these are not actually a species of ant. It is just what ants that are looking for a sugar/carb based food are called since they go for sweets. We would suggest using either the Indoor or Outdoor Ant kit depending on where you are seeing activity.
Sugar Ant Products/Kits
How to Get Rid of Ants Treatment Guide
Termites do not normally attack live, healthy trees so you most likely will not find any products that will work as a ground barrier around the trees. Most people are primarily concerned with protecting the big investment, their home, and Termidor SC would be the product to use for that. It is only labeled to be used adjacent to the structure though. Please take a moment to read over our article on "How to do a Termite Treatment" for complete details.