My text seems to say that the high(est) energy orbitals are not valence orbitals - everything else says otherwise. What's true?
The problem is the words used to describe energy. I am not native english speaker so I am not the best person to answer your question but I'll try.

As smaller $n$, smaller energy. Problems arises when the words higher lower are used to compare numeric values (as those of the energy). They must say greater or smaller.

Without accurate words all of us intuitively agree in that:
"2 is higher that 1", and we should say that 2 is greater than 1 (2>1)

When negative numbers are involved it is not so clear. For some authors "-2 is higher than -1" and "-2 is higher than 1", for others "-2 is lower than -1" and "-2 is lower than 1". In the later cases the correct word is "smaller" (-2&lt;-1).

In this context energies are negatives because of the definition of the reference states. So the energy of an $1s$ orbital is smaller than the energy of a $2s$ orbital.

I have some discrepancies about the meaning and usage of orbital energies but I adopted the common usage to avoid extra confusions.