Would "Human Resources are excited or is excited" be correct?
In the example given, Human Resources is shorthand for the Human Resources Department. It is logically singular. As such, the verb should be is.
There are some cases when a plural might be called for
In many modern companies, human resources are their most valuable assets.
Note that, in this latter example, there is no capitalization, since the phrase is not the name of anything, but a generic descriptor.
SUPPLEMENT: The above explanation reflects US usage. Other English speaking countries may differ.