Waiting times here can be anywhere from 1-2 hours to 10 hours. There are no food shops in the waiting areas so it will be worth packing some small food to keep you going. Due to the number of pilgrims coming into the country, processing can take longer than normal airports. In recent years, however, the process has gotten a lot better with pilgrims spending a lot less time at the airport.
Remember you are the guest of Allah, practice every bit of patience and continue to recite the Labbayk.
Jeddah airport can be a good place to purchase a SIM card, if you get a chance, otherwise there are many shops in Makkah too. To obtain a sim card you will need to show your visa and passport.
There are several companies such as Zain, Mobily and STC. Instead of getting hung up on which company to go with, it would be better to look at what data deals they have on offer as you will be using data to call home.