Get used to it.
Jardini's are skittish until almost fully grown. Don't keep large rocks in your tank or any other sharp decor as the arowana will impale himself eventually on it. He'll knock scales off from time to time also, they'll grow back. You can turn your lights on a while before you want to watch your jardini also, like turn them on when you wake up and leave the room for a while then come back.
If he gets too out of hand just turn off the lights and walk away, make sure he cannot jump out of the tank though. The more you get him used to the light the less he'll jump all over, but remember that your light is mostly for you, not for him. So always just turn it off if he gets worked up too much.
Any questions PM me, or refer to the vids in my sig, they show a lot of different Jardini behaviors.