The most common and most likely answer to this crossword clue is the 9 letter word GRADUANDS
I've seen this crossword clue in The Guardian
G
R
A
D
U
A
N
D
S
Buddy explains!
The straight part
We know that "they are waiting for a conference/they are waiting for a conference" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they are waiting for a conference/they are waiting for a conference = graduands.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 GRADUANDS mean?
GRADUANDS noun- A student who has completed the requirements for, but has not yet been awarded, a particular degree.