Q: Is there a need or way to turn the pencil off when not in use ? ?

Unfortunately not. The best thing is to switch bluetooth off. However, you will need to re-pair the iPad and pencil again by plugging it into the lightning port. When not in use the apple pencil does not loose a great deal of power.

There is no need to turn it off (and it can't be turned off).  However, when you stop using the pencil, it goes into a low power mode, and disengages from the iPad Pro in terms of bluetooth connection.  At the moment you pick it up, it will reconnect to the iPad Pro.  Therefore, it uses very little power when not connected to the iPad, and is not an issue.

You can see this is you have set your Pencil down, and waited a while.  When you turn on your iPad, you'll see that the bluetooth is not connected.  Then just pick up your Pencil, and you'll instantly see the bluetooth connect.

sam 26-01-1996 wrote:

 

Unfortunately not. The best thing is to switch bluetooth off. However, you will need to re-pair the iPad and pencil again by plugging it into the lightning port. When not in use the apple pencil does not loose a great deal of power.

No, you should not have to re-pair it, just as you should not have to for any paired device. You can turn BT on and off as you wish. To get the pencil active again, just enable BT, tap the screen to activate it and start using it. Pairing is retained even with a complete iPad shutdown and restart.  Simply picking up the pencil and starting to use it again will awaken it from low power standby mode.

After iOS 9.3.1 I have to pair the pencil anytime I shut down my iPad pro 12.9 inch.  I tried shaking it but it still does not wake up. So I have to stick it into the Lightning port and pull it out. It 98% charged from yesterday, its not a charging issue.

edit - I made a post over a week ago, but got no answer.