I thought the Kent Test was meant to be 'Tutor proof'?
It is certainly different and more in keeping with what the children learn in school. However, you still have a reasoning paper and spatial awareness questions which will not be covered by the school curriculum. It is also useful for your child to have experience of what to expect. This will include the speed that they need to answer, shortcuts and tips for tackling certain questions.
Do you set homework?
I might give your child a challenge question to solve or a puzzle but that is entirely optional. I'd rather they played Minecraft, read a book or enjoyed some physical activity. Never underestimate how important just having fun can be! :)