Consider this question:
Where are they (things or people)?
Would the following answer be with (at), without it or either one?
I left them (at) home
I have done a quick Google search and found quotes for both cases, with and without:
This Widow's 4 Kids Were Taken After She Left Them Home Alone.
Leaving Your Child Home Alone - KidsHealth
Gerry said, "I left them at home." Gerry sat down and turned on the TV set just as Mark would have done.
I read about "home" being an adverb but also know "stay at home moms" for example. So you see I need definite answers.