there is one option of denoising data under Passes-> Data, are they same? Because my render Image had still a good amount of noise, (it took 3 mins for one image, damn, Its going to be hours for the final)
In 2.9 several Render Denoisers can be found in the Render Tab:
NLM is the 'classic' one that was used in the tutorial, I think. You might even have more options (if you have Optix,....). You can make a comparison to see which one looks better/ is faster...
The Denoising Data is meant for the Compositor (you can add a Denoise Node in the Compositor after you've rendered all images).
Oh, and don't forget to enable Adaptive Sampling (also under Sampling in the Render Tab), probably makes a huge (speed) difference in the rocket scene.