No, please don’t move at all. Don’t adjustment or move the body in any way. You can swallow and slightly adjust the head if necessary, but that’s all. It’s important to keep still, because the Jhana state will develop faster when there is no movement. It’s like ice trying to freeze. Don’t touch the water while it freezes.
Giving attention to the itch will make it worse. So, if your attention gets drawn to it – you forgot you were meditating -, you can apply the 6R’s and Return.
Remember that sittings are always at least 30 minutes. So, get in an alert, comfortable position beforehand.