Introducing a kitten into the home ..

[pombearcat]

We're getting a kitten in two weeks time ...he'll be 9 weeks old.
It is a while since I had a kitten so if anyone has any tips on how to introduce him to our existing (rescue) cat who is about 2years old who sleeps mainly.. eats....sleeps again.. you get the idea!
Should I introduce them from the off or keep kitten separate for a while? (I have an small dog crate he could sleep in a night maybe ..with a litter tray etc )
Existing cat mainly uses the sofa ..doesn't go upstairs and only in the kitchen in order to open the frigging fridge door to help himself to cooked meat and cheese .
Any advice gratefully received ..