Really like some of the ideas here

We have a 'special ball' that we hand out at the end of each match. 
Each player has a target that they say they want to work on and the ball is awarded to whoever the kids decide tried the best. Obviously we guide this so that everyone gets the ball but try to make it feel like the kids came to it

Love the idea of getting parents involved too

I have 3 U9's teams and we all have a player of the match (MOTM), this is awarded by the parents in our first game of the season. That player is then the team captain in the following game and his (we only have boys) parents select the player of the match in that weeks game. This works really well as the parents have involvement and  the player loves the opportunity to be captain.

i give the parents a brief on the criteria so that its not just the player who scored the most goals for example, effort, listening and team play is of importance.

We are U9s and this season and last we gave the armband to one player for how well they trained, then every week after the captain chose the next captain for the next match. We set guidelines and although every now and then it went to best friends, usually there was sound reasoning around effort, trying new things, and general improvement. They also k ow that once they’ve been captain they can’t again until the whole team has.
Someone else mentioned end of season awards and so far although having a team celebration we’ve not given individual awards.

I have a mixed team of boys and girls and I award a player off the match based on our team agreements. Hard work, trying something new, daring to be creative, making yourself hard to beat, how well we play and our values of persistence, respect and teamwork. Not the scoreline or assists. First match of the season we won 4-3. My main striker got all 4 goals but I awarded to my defender who in one individual moment lost the balk but then immediately won it back, controlled the ball, shielded from the press, beat her opponent, dribbled forward and started an attack that led to a goal. Point is if you use it in the right way and have the team and parents bought into it, it can be a very powerful and motivating way to reward and recognise development, build confidence and self belief 

We don't do player of the match. Nor do we give out awards at the end of a season. I think if the right praise is given then that should be enough. Players play because they love the game.

We try to build a culture where players want to improve because they love playing. Keeping sessions and matches fun keeps the motivation. I set the challenges for individuals based on the review of previous learning and knowledge of the child's responses and motivation to those challenges. 

Its important to  link the parents into those challenges and that culture too. 

It works for us but that's not to say you can't use rewards. 

I never award man of the match as not only are they not men, but they arent all male either