We have put together useful resources that will help you in OCP8 exam preparation here: useful resources.
Are the books (Java the complete reference 9th Edition) with (java 8 in action) enough ?
No, not really - they are excellent books, but they do not cover the breadth and depth of topics required for cracking the OCP8 exam. Take a look at the Oracle's exam page for 1Z0-809 - you will find that it covers a wide range of exam topics. So, I would recommend a reading a book that is meant for OCP8 preparation - this approach is especially useful if you are pressed for time and can afford only limited effort for exam preparation.