The most common and most likely answer to this crossword clue is the 9 letter word CHRYSALID
C
H
R
Y
S
A
L
I
D
Buddy explains!

The straight part
We know that "developer’s case" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case developer’s case = chrysalid.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.
What does CHRYSALID mean?
CHRYSALID adjective- Of or relating to a chrysalis.
- The pupa of a butterfly or moth, enclosed inside a cocoon, in which metamorphosis takes place.
- The cocoon itself.
- A strong constraint; shackles.