Car Hire or Bus from Xi'an to Terracota Warriors on Wednesday

We are visiting Xi'an this week and are trying to squeeze in a trip to see the Warriors. We can leave our hotel at 10am and need to arrive back no later than 5pm. Is is possible to do this trip by bus? It looks like we could take a cab to the 306 at the Railway Station and then head out and still make it back in time. If we take the 306, would we need to transfer to another bus or just get off at the last stop? Also, what would it cost and do you have any recommendations for a car hire? Given out limited time, we want to make sure we can squeeze it all in.

Thank you!!