The most common and most likely answer to this crossword clue is the 9 letter word GRANULATE
I've seen this crossword clue in The Guardian
G
R
A
N
U
L
A
T
E
Buddy explains!

The straight part
We know that "go to bits" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case go to bits = granulate.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 GRANULATE mean?
GRANULATE verb- To segment into tiny grains or particles.
- To collect or be formed into grains.
- Consisting of, or resembling, grains; crystallized in grains; granular.
- Having numerous small elevations, like shagreen.