Hi! 6 and 9 are the most commonly confused numbers in that age group. It is because the shapes are similar and inverted. So I don't think it is dyslexia if she understands other numbers.
There are 2 things you can do.
1) How do you draw 9? is it curved as it looks here or like a mirror image of P? If she is confused, you can swap the way it looks.
2) This should be the first one, ideally. Children are confused because they do not understand the concept of numbers. Make her count and draw!
You can also give her cooked spaghetti to play with, to form numbers out of it. It is a fun way to learn how to write/draw.
The key is repetition. So be patient, and everything will fall in place.
p.s. I used to be confused between p and q; and b and d. It is common, so don't worry!