Dear Dhruv 

Yes you can surely crack IIT by prepearing in 1 year. If your basics are clear and you are regular with your studies, you surely can.

If you have joined coaching, give time to your self study also. Make proper schedule and follow it. Sometimes  you may feel demotivated that moment think you have to go iit and make yourself motivated and start studying.

And as you are dropper you don't have to go  school and perform rest things so it's your plus point to just focus on jee preparation without any delay. 

All the best for your preparation!