It is known that children are more likely to behave badly when with adults they trust will still go on loving them. So, do not worry about setting your own boundaries. Children also need and want these for safety, even when appearing to push against them.
As has been said, after being at school for several hours, where they have been trying so hard to behave themselves, they need time, to be able to relax and not have to think about this when they get home. Even more so if the weather has been bad (as it often is this time of year), and young children have been kept indoors for 'wet play' during their break times.
When I used to run a children's gymnastic club, our first evening class each weekday was for 4 & 5 year olds, and it was always noticeable how differently they behaved when they had been on wet play days.
Set your rules, keep to them whatever they are, but also allow plenty of time, for cuddles and listening to them. They will love you all the more for knowing exactly where they are with you.