1. Enough time for the shuttle
2. You will have to collect your bags and clear customs with them im BOM. From the current info on their website 9W may have a drop point in T2 after customs:
http://www.jetairways.com/EN/IN/Prod...hServices.aspx
Airport transfer at Mumbai
Jet Airways transit guests can avail of Inter-terminal Shuttle Coach service operated by the Airport Authority of India (A.A.I.) within the Tarmac from Mumbai Domestic Airport to International Airport.
Transfer from International Airport to Domestic Airport
Once you arrive at the International airport, proceed from your respective gates towards the Passport control lanes. Avail of the dedicated priority lane for quick processing- a facility for the First class and Première class guests.
On completion then move on to collect your baggage from the conveyor belts and then clear customs.
Once this is done move towards the domestic transfer area within the arrival hall
Here, you can relax in the air-conditioned comforts of the waiting area for domestic transfers.
At the domestic transfer area, deposit your check in baggage at anyone of the Jet Airways transfer desks.
Then feel free to board the complimentary inter-terminal coach service, which leaves at an interval of every twenty minutes.
The coach service will then ensure that you reach the domestic terminal on time to catch your connecting flight.
If not, you have to carry the bags to the shuttle and collect them in T1B to recheck them with 9W there.