Hello, 

It is not necessary to take any coaching classes to get a good rank in NEET. However, a coaching class has certain advantages like it will guide you properly about how to prepare and what points to focus on with proper time Management. A coaching institute will provide proper notes which are sufficient enough along with NCERT books for preparation. A coaching class will also provide with mock tests for proper time management in solving your paper in time. 

You can do all this at home also by studying from NCERT books and there are many previous year's question papers available on the internet which will help you to prepare for the exam. 

You are dropping a year for NEET preparation so I assume that you know what the exam is and how to prepare for it. 

Therefore, I do not think a coaching institute is necessary for you.

Hope this helps.

Good Luck.