The most common and most likely answer to this crossword clue is the 3 plus 3 plus 6 letter word FOR THE FALLEN
F
O
R
T
H
E
F
A
L
L
E
N
Buddy explains!
The straight part
We know that "Poem read as memorial" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case poem read as memorial = for the fallen.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.