Today the poet writes a poem would also be correct!
2019-09-23 Well, since poems were commonly sung, they're really the same thing, right?
Timor mortis conturbat me.
I think "poet" is more on "poeta" than on "vates".
It marked "hymn" as incorrect. I guess that's what comes of only reading late- antique and medieval Latin.
I submitted, "The poet writes a poem today" to be accepted as correct.