my hp officejet pro 9015e is connected to ethernet but i want to use wifi, do i need to unplug the cable?

Nope, you can leave the Ethernet cable plugged in. Yeah, this one's common. If your computer is connected by Ethernet, you just need to turn on the computer's Wi-Fi while you're running the printer setup in the HP Smart app. The software will handle the rest. You don't need to physically disconnect the Ethernet cable at all.