The most common and most likely answer to this crossword clue is the 9 letter word PREAMBLES
P
R
E
A
M
B
L
E
S
Buddy explains!

The straight part
We know that "Introductions to" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case introductions to = preambles.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 PREAMBLES mean?
PREAMBLES noun- A short preliminary statement or remark, especially an explanatory introduction to a formal document or statute.
- A syncword.
- To speak or write a preamble; to provide a preliminary statement or set of remarks.