I've name changed. Can't be arsed with a flaming.
I purposely infected my dc with chickenpox (took them round on a play date with an infected child).
It was horrid, they were ill, and now they're fine.
I researched chicken pox very carefully before hand (and I know that some children can get very very ill with it and with a depressed immune system it can be fatal). I also discussed it with several doctor friends who thought the idea perfectly reasonable.
They were in the rudest of health when they caught it.
I was able to stock up on all the pain killers and creams (and do a MN archive search) before they came out with the spots. I also stocked up on food, and dvd's etc.
Because you are infectious 2 days before the spots come out I kept them off nursery and housebound so they couldn't infect anyone else.
Catching Chicken pox is almost certain at some point in your life. I wanted to get it out of the way at a time that was convinient for me, and for them (no holidays planned, school trips or plays, birthdays etc).
Saying that imo 9 weeks is too young.
Flame away, it was the right thing for us to do at the time. I'm logging off now.