Delta-8 THC is pure Tetrahydrocannabinol (THC). It, just like Delta-9 THC in marijuana, will show up as THC on a drug test.
Although Delta-8 THC comes from the Hemp plant (CBD), it is not CBD. CBD and THC have different effects. CBD does not cause psycho-active effects, but has been shown to "help" with a lot of different health issues. THC in fact does cause psycho-active effects from both the marijuana plant (delta-9) and the hemp plant (delta-8); it is also known to help with a lot of health issues as well.
So although Delta-8 THC comes from CBD.. it is absolutely not the same as CBD... and will show up as THC not CBD on a drug screening.