how can i configure MikriTik 1100 router not to give internet asses from 8am to 4pm

look up time attribute in here:
http://wiki.mikrotik.com/wiki/Manual:IP/Firewall/Filter

how can i configure MikroTik 1100 router not to give internet asses from 8am to 4pm

You are able to write a script, that is disabling the LAN ports or wan ports like you want, at one time you want
to prevent peoples from using the internet and enabling this ports again at another time you need the internet access,
once more again.

It is not the best method for doing so but if you have more then one kid in your house hold and they have different
ages it´ll be the best to disable the LAN ports where the Kids computers are connected, so you are able to chose
different time frames for each kid.

look up time attribute in here:
http://wiki.mikrotik.com/wiki/Manual:IP/Firewall/Filter

+1... either that or use a script. But depending on how you do it they may be able to circumvent it by changing their IP.

look up time attribute in here:
http://wiki.mikrotik.com/wiki/Manual:IP/Firewall/Filter

+1... either that or use a script. But depending on how you do it they may be able to circumvent it by changing their IP.

If there will be a method or change to set up a MAC > IP address binding they will not be able to do so, or better
changing the IP will have no effort or effect for the children. Would this be a solution?

I use DHCP on my RB with static MAC<->IP matching via the ROS user manager feature.

Each MAC address only gets exactly one IP address and manually configured addresses won't be accepted (they won't get an ARP entry).
Each such user has a profile assigned and these profiles can carry limitations (which I don't use myself). The limitations can be each day of week and a start and end time.

This setup is a little bit tricky to setup at the beginning but pretty easy once you got it figured out.
Of course, this only works if you force all computer's MAC addresses to be configured before they can access the LAN.

Zap.