That's correct. M9, i.e. the SuperHighway is currently under renovation as they are upgrading it to a motorway, so the condition of the road is pretty bad and can take up to 5 hours to make the trip, depending on what time you're travelling. Another alternative is the National Highway - Hyderabad, Kotri, Jhirk, Thatta, Makli, Gharo, Karachi, route. This is a narrow road, but in the current circumstances, should save you time.
Look it up on Google Maps
