We took our 8 year old to Cairo and I would echo everything that AS219 has said. The things our children most enjoyed were:-
- Pyramids especially going inside and the Solar Boat
- Felucca ride
- Egyptian Museum
Our hotel arranged a private guide and transport at a very reasonable price and it made all the difference. He was able to get us into tombs that are usually closed to the public and we bypassed all the queues. Our children also learned so much from him - it was worth every penny.
The only thing we did that I would not recommend was Cairo Zoo. We thought our children would enjoy it but it was dreadful and quite upsetting for our little girl as some animals were clearly in distress.
I agree with AS219 that I would not stay in a hostel in Cairo with an 8 year old.
Whatever you decide have a great trip.