Solarbabies

The story is set in a post-apocalyptic future in which most of Earth's water has disappeared. The future is bleak and what is left of the water supply is controlled by the Eco Protectorate (a para-military organization that governs the planet's new order). There are also children, mostly teenagers, living in orphanages created by the Protectorate, designed to indoctrinate new recruits into their service.

The Warden: "I am the warden of Orphanage 43, one of the many orphanages that border the wasteland. Children are brought here at an early age to be indoctrinated to serve the system. It hurts me to do that to them. I too, must serve the system."

The protagonists consist of Jason, the group's leader played by Jason Patric; Terra, played by Jami Gertz; Tug, played by Peter DeLuise; Rabbit, played by Claude Brooks; Metron, played by James LeGros; and a young deaf boy named Daniel, played by Lukas Haas. The orphans play a rough sport which is a hybrid of lacrosse and roller-hockey. The titular Solarbabies have (through their experiences and friendships on the team) managed to forge a bond that unites them and transcends the futile attempts of the Protectorate to control them.

While hiding in a mineshaft, after a game broken up by the Protectorate, Daniel finds a mysterious orb with special powers. The orb is apparently an alien intelligence called Bohdai, who miraculously restores Daniel's hearing and has other powers, once even creating rain indoors. Daniel takes the orb back to his companions, but another orphan, Darstar, impressed by its abilities and power it promises, steals the orb, hoping to present it to the Tchigani, his native people. He leaves the orphanage with first Daniel and then, as a result, the rest of the Solarbabies in hot pursuit.

What follows is a pretty standard 80's post-apocalyptic child-empowerment romp fueled by the power of friendship as the Solarbabies risk life and limb to protect the orb (and each other) from the machinations of the oppressive Protectorate.

As an interesting sidenote, the film was renamed Solarwarriors in the UK. (possibly to make it sound tougher)

Tropes used in Solarbabies include:

After the End: You better believe it. Bonus points for also being barren due to lack of water.
Big Damn Heroes: The appearance of the Eco Warriors to rescue the protagonists from bounty hunters certainly qualifies.
Bounty Hunter: see above.
Do-Anything Robot: Gentlemen, this is Terminac. He is a multi-capable masterpiece. He can squeeze the colour from a ruby or deftly pluck the eye from a living bird. And he is programmed to enjoy what he does.
Fridge Brilliance: Given that the institutions housing the Solarbabies are explicitly referred to as "orphanages" it may seem odd that Terra's father is still very much alive. However Unfortunate Implications abound when you realize that an unscrupulous dictatorship like the Protectorate isn't likely to split hairs about waiting for parents to die vs stealing children.
Groin Attack: Never get fresh with a girl holding a shovel.
Imported Alien Phlebotinum: The Orb (Bohdai)
Injun Country: Lots of this with Darstar's people the Tchigani.
Long-Lost Relative: Terra's dad - who happens to also be the leader of the Eco Warriors.
Meaningful Name: Bodhi. In the Mahabhrata, Bodhi stones are powerful orbs which granted enlightenment to the eight village elders the stones with given to. The word "bodhi" is also the Sanksrit word for "enlightenment."
Nebulous Evil Organisation: The E-Protectorate.
Opposing Sports Team: The Scorpions are shown, purely to introduce Corrupt Cop characters Gavial and Strictor Grock.
Outrun the Fireball: The Solarbabies do this at the end when Bohdai decides to destroy the facility by exploding. He gets better.
Tech Marches On: Daniel's "electric ear". Nowadays, he'd just wear a hearing aid.
- He would have "just worn a hearing aid" in the 80's as well. The cumbersome junky nature of the "electric ear" was a deliberate representation of the "scavenged tech" theme running through the movie.
The Eighties: If you've ever seen the trailer. In addition, the protagonists use "roller skates" in the far future setting - seemingly having never heard of "rollerblades"
The Empire: The E-Protectorate.
Tragic Hero: Darstar is a bit of one. He steals the orb in the hopes of restoring the spiritual power of his people, but unfortunately they've grown corrupt and his act leads to them being decimated or enslaved.

Terra: "Why did you take the sphere?"
Darstar: "Because I thought it'd do magic for me, like it did for you."

Wise Beyond Their Years: Darstar dips into this occasionally

Darstar: "I was raised in a Protectorate orphanage. That's all I know."
Chief: "What do they call you?"
Darstar: "I call myself Darstar."
Chief: "The owl, it's yours?"
Darstar: "As much as an owl is anyone's."

X Meets Y: Could be described as Mad Max meets The Goonies.