The most common and most likely answer to this crossword clue is the 9 letter word SYLLABLES
I've seen this crossword clue in The Daily Telegraph
S
Y
L
L
A
B
L
E
S
Buddy explains!

The straight part
We know that "Babies — there’s two there" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case babies — there’s two there = syllables.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 SYLLABLES mean?
SYLLABLES noun- A unit of human speech that is interpreted by the listener as a single sound, although syllables usually consist of one or more vowel sounds, either alone or combined with the sound of one or more consonants; a word consists of one or more syllables.
- The written representation of a given pronounced syllable.
- A small part of a sentence or discourse; anything concise or short; a particle.
- To utter in syllables.