Internet Home Schooling, if I took a course in a different country, would it still be creditable in the U.S?

If it's a US online school, then they should. If you're an expatriate in Guatemala, you may be able to attend your state's free online public virtual schools - as long as your family has a residence in the state while you're gone. Many military families use a virtual school in their home state while stationed elsewhere. Of course it depends on whether your state has virtual public schools. Otherwise you'll need to pay tuition to a non-public one.