Meursault,
2nd half of 9,20 is VESPER. (slack = VEER, around SP), but I don't understand all of the wordplay.
Re. the first playfair code square, I think that it has to be something like this:
U
F
C H
E A
R S
(CER have to be in a column, and HAS have to be lined up next to it).
but I can't get much further. Hint anyone?