Strength is arguably the most important component of fitness, and it is one of the hardest to develop. Therefore, it would be a good thing to focus on during the off season. You can start focusing more on metabolic conditioning once spring approaches.
The first thing I would do if I were you is to find someone who can run you through the FMS (functional movement screen). This will help you identify any basic movement limitations that you may have, which is important because such limitations are likely to increase your risk of injury and inhibit your performance. If you skip this step, anything you do is more likely to be counterproductive.
Once your cleared by the FMS, I would then focus primarily on strength training with a moderate amount of conditioning work for maintenance (until spring approaches).
If you choose to do CrossFit, make sure you choose a place with good coaches, and be mindful of overtraining. If you find that all they are doing is pushing you without really paying much attention to the quality of your movement, you should probably go elsewhere.