Figuring out IC pinout from the datasheet
I have labeled what I think is the pinout on the IC, with green numbers.
Is my assumption correct?

Yes!

Is my assumption correct? What about pins 9-16? Are they in the correct order?

Yes!
Your numbering shown in green is correct, for all the reasons you stated.
Here is your photo of the IC with green numbering, rotated clockwise by 90° so the circular &quot;dot&quot; (indentation) is top left, to match the image in the datasheet.

Now you can clearly see that your green numbers match the pinout numbering from the datasheet.