A VOR radial is identified by its magnetic direction from the VOR station. The 090 radial is the line extending east from the station; the 270 radial extends west.
RememberRadials are always FROM the station. Your airplane can be flying toward or away from the station while you are using the same radial.
What the CDI is doing
The CDI tells you where the selected course lies relative to the aircraft. The important part is to know whether you are using a course that takes you toward the station or away from it, and whether the indication is sensible for the direction you intend to fly.
A useful cockpit habit
Before twisting the OBS and chasing the needle, say the plan out loud: “I am here, I want to go there, this is the course I need, and this is the station relationship I expect.” That simple verbal check catches a lot of errors.