First off...breathe!
I know, leaving them the first time is SO hard. But I am sure that Mufasa will be fine. Cooper stays home while my husband and I are at work and we've had no issues (knock on wood).
Cooper loses his mind when I get home, so be prepared for dramatic welcome. But my guess is he spends most of his time lounging in his crate.
Of course, you should leave a comfy place to sleep, food, water and toys. Some people also suggest leaving a tv or radio on to keep the puppy company.