This is not extremely difficult but it has a few parts to consider. What scanner are you using? Do you have it working to bring data into FM already?
After that it is a simple find to locate the correct student.
From there the selection can be made with buttons that "Hide" when Get(CurrentTimestamp) > The set cutoff time.
The email can be done with a report type layout emailed by script to whoever needs it.
It's unlikely that anyone will hand you a ready made solution for this so the real question is whether you are up to the challenge of learning FileMaker and Relational Database design sufficiently to create this for yourself.
I do recommend that you break this down and ask for help with one feature at a time. So I am going to ignore your other requests for now and focus on scanners.
You can scan bar codes or magnetic strips with add on hardware you attach via USB to a computer. You can also scan bar codes using the camera of an iOS device such as an iPhone and an iPad. Which method you use determines which of two fairly different approaches to use.
For a scanner attached via USB, your computer perceives the input from the scanner just as though someone had rapidly typed the scanned info on a keyboard. Thus, you can put the cursor into a FileMaker data field, scan a barcode or magstripe and the scanned text will appear in the field. Many scanners can be configured to put special characters before and after the scanned information. You can use FileMaker script triggers to respond to these special characters to a) put the focus into the correct field to receive the scanned info and b) trigger a script to process the information thus scanned.
I set up a system for scanning the MagStripe on CA drivers licenses and parsing the scanned info into various fields in a purchase invoice for my previous employer. Using the scanner they had, I configured it to precede all scanned info with shift - caps lock ~, a three key combination that was very unlikely to occur by accidentally leaning on a keyboard. I configured it to append a tab character to the end of the scanned text.
So I set up the OnLayoutKeystroke trigger to run a script that checked for the shift and capslock modifier keys as well as ~ as the first keystroke. If so, it used go to object to put the cursor into a global text field and then stop.
I set up the OnObjectExit trigger on this same field to perform a script that then parsed the data.
So your first task is to see if you can get your scanner to work in similar fashion and put data into a FileMaker data field with a script that at least pops up a message telling you that the appended character at the end of the scan was detected. Once you can do that, you can post back here with your next question.
Be prepared to spend some time figuring out whatever method (if any) was provided by the scanner company for configuring it in similar fashion to what I did. Not all support all possible "prefixes" and "postfixes" so you have to adapt your solution to work with the options that are possible for your hardware.