Ah, this half-ten is nine thirty thingie must have been borrowed from Dutch, no?
It's true that it's similar, we say it like: quarter over nine, half ten, quarter before ten, ten hour
"Is it nine-thirty?"
Should add "now".
"Is it nine-thirty now?"
pukul setengah sepuluh translates to "nine thirty" or "half past nine"
So, it should be: Is is now "nine thirty"? or Is it now "half past nine"?
The "now" is very much superfluous in English and should be accepted without it