The most common and most likely answer to this crossword clue is the 9 plus 3 letter word SPELLICAN (A)
S
P
E
L
L
I
C
A
N
(
A
)
Buddy explains!

The straight part
We know that "Driller’s pipe? Pair" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case driller’s pipe? pair = spellican (a).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.