I’m going to answer this as a former soccer player/coach/referee instead of the mom of a child with hemiplegia, since I know more about the first.
Being a good soccer player is more about ball control than how hard you can kick the ball. Of course, kicking is an important skill, but trust me, a young child who can dribble will have any coach feeling grateful for receiving such a player.
Some dribbling techniques that I used with little ones (who were uncoordinated even WITHOUT hemiplegia), were to encourage the kids to walk the way they normally would, but with a ball at their feet. The trick was not to take a step without being able to touch the ball. The key to success on this one is to stroke the ball, using either the inside or outside of the foot, NOT the toe. As Thomas gets more comfortable with this, he can increase his walking (running speed), slowing back down if he loses control with the ball. If you have plastic cones, he can work his way in and out of those.
Once dribbling is an established skill (and don’t despair if it takes a while, some of my High School age players still didn’t do it properly), he can practice passing (another rare but oh so necessary skill). Starting with someone else moving along side him, have him gently tap the ball to them using either the inside or outside of a foot. Again, once his confidence gets built up, his taps become harder and I’m sure you’ll find he’ll get more distance on his passes.
As far as kicking is concerned, having an affected foot may not be the hindrance you might think. I always found that the most distance and best accuracy on my still kicks came from connecting with the ball with the laces of my cleats. In other words, toes pointed down to the ground. Hope this helps. Good Luck! – Heidi Jameson