The most common and most likely answer to this crossword clue is the 9 letter word AUXILIARY
I've seen this crossword clue in The Guardian
A
U
X
I
L
I
A
R
Y
Buddy explains!
The straight part
We know that "Should say/type of verb" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case should say/type of verb = auxiliary.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 AUXILIARY mean?
AUXILIARY noun- A person or group that acts in an auxiliary manner.
- A sailing vessel equipped with an engine.
- (grammar) An auxiliary verb.
- A marching band colorguard.
- Helping; giving assistance or support.
- Supplementary or subsidiary.
- Held in reserve for exceptional circumstances.
- Of a ship, having both sails and an engine.
- (grammar) Relating to an auxiliary verb.