If you have "modest" environment you might not have a radius server. If you have still not a simple click a few buttons job.
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This might seem overkill for one device but it'll do what you want. Could regard it as a quick dirty fix.
Create a new WLAN called IPAD
use an ACL list with the ipad MAC in it and assign that list to IPAD.
screenshots in a minute.
In ZD
configure
access control
L2-L7 access control
create new....
add in MAC of ipad...save
create new WLAN
configure
WLANS
create new... edit as required
access control drop down menu should have the IPAD ACL list (you previously created) as an option.
As John correctly mentioned this is not as secure as other methods and is not "good practice" unless you know how to lock your IPAD WLAN down in other ways.
Minor simple improvements include
not broadcasting the IPAD wlan,
restrict to one client (yours) for the WLAN on that AP (stops any other device from connecting)
restrict it only to IOS devices,
assigning WLAN to only one of your APs on 5GHz,
reducing the power output of that AP WLAN to minimum needed,
scheduling the WLAN (7AM-7PM say),
limiting throughput...
look through the options and figure out what you need bearing in mind they can occasionally have unintended outcomes!
If you restrict to one client connection and add in a long inactivity timeout (say 60mins...if you are busy practice then that shouldn't be an issue) the ipad would hold the connection and no other device could use that WLAN.
etc