You have to go through a security check at Terminal 1. The El Al web site says: Please arrive at the check-in counter at Eilat Airport / Ben-Gurion Airport Terminal 1 at least one and a half hours before the flight, i.e. 10:40. This means that you have to get on the shuttle by 10:30. In Terminal 3 you have to walk to immigration, do the immigration check and pick up luggage (usually arrives on the carousel very quickly at TLV compared to other airports). So if you arrive at 9:45 AM you have 45 min to get out and to the shuttle. Personally, I would book a later flight .....