The most common and most likely answer to this crossword clue is the 8 letter word STEADIED
I've seen this crossword clue in The Guardian
S
T
E
A
D
I
E
D
Buddy explains!

The straight part
We know that "made stable" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case made stable = steadied.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 STEADIED mean?
STEADIED verb- To stabilize something; to prevent from shaking.