Dividing Paper: Easy Method
Take a sheet of paper that is larger than the sheet you will use for origami. Fold it into equal-distant segments. Shown here, the sheet is folded to have 16 divisions. This is your template.
Place your origami paper on top the the template. Angle your paper so the two corners span the number of division you want.
If you want to fold your sheet into thirds, angle the yellow paper so it spans over 6 segments of the purple template. Draw a small line (or make a small fold) at the location where the creases should be.
This easy method of dividing paper can be used for dividing paper into fifths, sevenths, and more.
How many segments you need to fold the template depends on the sizes of your papers. In the example shown here, it would have been sufficient to fold the template into 1/8 divisions to determine 1/3 division of your origami paper. This is shown below left.
You would have to fold the template into smaller divisions (32nd) in order for it to be useful for determining 1/9th division of your origami paper.
Indeed, you do not need to make a template at all. A sheet of paper with lines pre-printed on it will suffice. Shown below is a template made with lined-paper commonly used in classrooms.