WPS pin on an HP Officejet Printer is an eight digit number which acts as a code of security when you connect your device and the PRO 9010 printer wirelessly. This WPS Pin gets generated when you are going to have a connection which is wireless and also the pin will always be in numeric form.
The WPS connection is a safer and securitive mode of connection between two devices. The WPS Pin is the auto-generated code and it will change each time like in the case of your OTP.