Read LED state without any relay or button

Using Arduino LEDs and Multiplexing
#1

This is a very silly question. I am a newbie in Electronics and Arduino. I want to know if i can get the current status of LED which is connected with a 9V battery. I tried to read using digitalRead but it is always returning 1 no matter what.

All i want to know is, If i turn ON some equipment using arduino and relay, Is there any way to check that the equipment is really ON?

I'm using NodeMCU v3 Wifi.

#2

One important thing is that you must never connect a voltage greater than he processor’s rails to any input. So connecting a LED that has one end connected to 12V is going to damage your Arduino.

You need to post a schematic of how you are wiring this up before we can tell you if you are doing it wrong.

#3