Maybe you have a typo, he’s asking about Object Detection which is different from multi-label classification. Object Detection is indeed studied in lessons 8 and 9 of part 2 v2, but the code that comes with those lectures is only working with fastai v0.7, not fastai v1.
I’m not aware of any “easy” way to implement Object Detection with fastai v1 right now. One way is to try to port the code from lesson 9 v2 to fastai v1, but I wouldn’t call that easy.