Airlines of India - Any recent transit experience BOM/DEL?

A relative of mine recently did a 9W domestic to CO connection in DEL and mentioned not having to collect/recheck baggage. Is this a new change? How about in BOM?

On interline, flying out of India, yes, BOM does that if the luggage is checked in thru to ultimate destination.

Hmm, OK. I doubt I can get 9W to check the bags through, especially on separate tickets.

But flying into India, I doubt bags could be checked for collection past BOM/DEL if flying on a domestic segment, right?

I called 9W and they mentioned that you still have to go through customs in BOM, although there is a baggage drop-off point and pax can check-in at the international terminal for the domestic leg. That's nice, so I don't have to haul all my bags to domestic (as used to be the case).

I have an overnight layover in BOM (~9 hours) and this makes it a bit easier to visit someone outside the airport.

Right. Its because of customs, that they can't through-check in the bags. But their transit counters (at least BOM, I know they do this) will scan the bags at the transit area to domestic, issue you another boarding pass, and get you going. But all this is after customs. You have the option of taking the inter-terminal coach to the domestic section - even if you do that, you don't need to identify your checked-in bags again.