Why do you want to shut down the Pi? The Pi itself uses so little power (<5W) that it is not worthwhile unless you are running on batteries. The B+ uses even less.
EDIT 2016-06-18 The following comment is no longer correct.
poweroff all perform a orderly shutdown of the OS.
Having said that
halting the Pi puts into a very low power state, but can only be restarted with external events. It is simple to "restart" the
B+ from the
halt state using a simple externally driven circuit. This could be a timer or even a light dependent sensor. see https://raspberrypi.stackexchange.com/a/19754/8697
If your motivation is to limit access you can use
cron to close down the relevant services and/or power down external devices. You would leave the Pi running to restart the next morning using a