Hey All !! Please let me know if we could hide this"Quantity Available" section through configuration or website setup?

that does not look as out of the box, it´s likely to be an extension

Yes, is this not a feature of the Inventory Display extension? https://netsuite.custhelp.com/app/answers/detail/a_id/82959

No, its not a feature of Inventory Display . its by default showing "Quantity Availablity Message"