You can check with the person you are getting your kitty from on what the cat is currently using and continue to use the same litter. This way, the cat is already used to it and won’t have much problem using the litter box.
Get the biggest litter box you can as kittens grow up very fast and they outgrow the box. Also fill up the box with at least 3ins of litter so that it’s easier to clean the box as low litter will most likely to have pee stuck on the bottom.
I've switched to wood pellets and it's brilliant. It's far cheaper than other types; it's fantastic at covering odours and it just falls out when emptying without anything sticking to the tray.
When I first used it, I sniffed the tray after emptying it and it just smelled of pine. Other, more expensive types have always reeked of urine when emptied. Great stuff.
Hello and welcome to TCS. Congrats on the pending adoption of your Persian. Do come back and post pictures when you bring him/her home.
About litter, how old is the cat? If it's a young kitten, you might want to start with non-clumping litter, as young kittens sometimes try to eat litter. But if it's older, any litter should be fine.
Maybe ask the breeder what type of litter they are using. It might be best to start with that, then transition to another type if desired.