Personally I wouldn't hide it from her, I would be very upfront with my concerns. Does she like to read? Have her start reading about her health. Have her start reading about our vitamin sources. Does she like to garden? Have her plant and care for a vegetable garden. Have her try different things.
It is hard to find an interest if you don't know all the possibilities. At 9, that could be the case.
Help her to understand what her body is doing and where it will go. Let her know where it can end up. She is growing and hopefully her body will balance out on its own. However, a good activity is always helpful.
Their palates are moving targets. They seemed to enjoy mushed carrots and peas, then refuse them, only to love them again. With that, I think you have to train their palates. Spinach is a loaded veggie, so I started out by adding about 3-4 finely chopped spinach leaves in the spaghetti sauce. Then it went to a handful. My 9 year old now loves spinach. She eats spinach and kale balls and loves them. I have to watch her though because I don't want a blood clot or a major colon cleansing.
With our oldest daughter, it did come down to, choose your sport or we will choose it for you. Eventually, she ended up with the wrong crowd, got in trouble, and we put her back on track with something positive. She chose dance and danced from junior high through high school.