Is there a AP that can be set up to change the key every day (for a retail establishment)?

I have a client that has an urgent care. They want to have wifi access for their patients in the waiting room (mostly for kids that have tablets without cell data). Right now, the wifi has a password that is posted in the waiting room. The problem is that right next door is a large apartment complex. I am sure with a directional antenna, the tenants of the apartments could see our network, and then if they visit the waiting room once, bam they can have the wifi password and be set.

I want to be able to either a) load a list of passwords depending on the day of the year, then the staff can give the correct password for the day or b) have a screen, LCD display (run by Rasberry Pi, Arduino, etc) that displays the current wifi password to patients or staff.

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Any AP out there that is capable of this? I know someone was doing something similar years ago with a 3rd party router firmware (Tomato, etc) but it was more for home use.

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Bonus points if the AP can be programmed with the hours of the business and shut down after hours.