What grade are my acne scars?

Thanks for your question. As best I can see in the photos your scars appear fairly shallow, mostly the 'rolling' type though you might have a box car type here or there. As far as grading you would likely fall into a grade 3. Here is a typical grading schema:
Grade one, macular, is a scar that’s red but flat. Grade two, mild, is a scar that can easily be covered by makeup or facial hair. Grade three, moderate, is “obvious at a social distance.” It is not as easily covered by makeup or facial hair. Finally, grade four, severe, is scarring that is very evident at a social distance greater than 50 centimeters (1.64 feet). It is unlikely that facial hair or makeup will completely cover up these scars.

You would be a great candidate for either Sofwave (microfocused ultrasound) or Morpheus8. Sofwave has the advantage of 'no downtime' and it is FDA indicated for the treatment of acne scars, but the heat is delivered to only a single depth. So, if the scar tissue is deeper than where the sofwave energy can reach, some scars may not be completely resolved. Morpheus8 has the advantage of being able to deliver heat at multiple depths and at depths deeper than Sofwave. So, Morpheus8 can address more pronounced acne scars- but there is some downtime of redness and puffiness. I hope that helps you!

Additional photos in varying lighting would have been extremely helpful here. However, from what can be seen there seem to be many superficial rolling scars, putting this in a Grade 1 or perhaps 2 category . If this is indeed so, then a Field Subcision of the cheeks would be a very logical first step for improving these. In general, Field Subcisions are accompanied these days by the addition of an HA filler whenever deemed necessary.
In your search for treatments, you will no doubt be hawked expensive fraxel laser or RF treatments. However, be cautious when evaluating these, since the hard science to back up their use lags well behind the heavy marketing hype and social media buzz to promote these gizmos. You would be wise to consult with a board certified cosmetic dermatologist scar treatment specialist, and best of luck.