Can't see the tail too well because it is in a shadow and kind of dark, but from what I can make out in this photo, it looks like a female.
Very hard to determine the sex from the photos. Plastron appears pretty flat and the anal scutes look like those of a female; however, the supracaudal scute has a curve back toward the body which males have, plus the tail in the newer pictures looks larger and longer than in the first pix which is another male characteristic.
By soaking he means you let your tort soak in warm water for 30 mins. This should be done at LEAST once a week if an adult. But I do not have any experience with this kind of tort so it might be a little different.
The tortoise looks older than 17 going by the appearance of its shell. How do you know its exact age if you have only had it for 9 years? Did you get it from someone who had hatched it themselves?
Soaking the tortoise means putting it in about 2" to 3" of warm water in a tub or container from which it cannot climb out and letting it stay in there for 20 to 30 minutes or so. You need to be sure the water is not too deep. In other words, it should not cover the tortoise's mouth and nose area, but should be just about up to the level of the lower part of the neck where it meets the shell.
How do you know its exact age if you have only had it for 9 years? Did you get it from someone who had hatched it themselves?
I agree with Yvonne. Today the tail appears shorter and less thick, and with those anal scutes pointing back the tortoise looks more female than male. I would still try the warm running water on the plastron as well as soaking it in warm water to see if it will happen to evert its penis and answer this question once and for all.