The boy from Slough, who cannot be named for legal reasons, was found guilty of murder on March 20 after a three week trial – he had also pleaded guilty earlier of possession of a bladed article.
He was only 15 when he fatally stabbed Elton in the chest in Salt Hill Park on September 21.
A post mortem concluded that Elton had died as a result of that one stab wound.
The boy was arrested on September 22 and charged the following day.
During the trial a jury hear how Elton Gashaj died when a 30cm hunting knife ‘around the size of a forearm’ was plunged into his chest by a boy also aged 15 – who claimed it was in self-defence.
A group of 10 boys had earlier pulled up pampas grass from the ground and removed the fluffy top turning the sticks into ‘play swords,’ prodding at Elton on the sunny September afternoon in Salt Hill Park.
Footage from the victim’s mobile phone which was shown to the court having been recorded by Elton as the teenagers poked stalks at him.
They could be heard saying ‘why you flinching’ just 15 minutes before the fatal stabbing.
After last week’s sentencing Senior Investigating Officer Detective Inspector Dejan Avramovic, of the Major Crime Unit, said: “This was a tragic incident, involving two young boys, that resulted in the death of Elton Gashaj.
“A boy has been sentenced to nine years and he will be able to spend that time reflecting on his actions.
“I would like to thank Elton’s family for their support throughout this investigation during what must have been a difficult process.
“Tackling serious violence is a priority for Thames Valley Police and it will never be tolerated in our communities. We remain committed to ensuring that offenders are brought to justice.
“Furthermore, if you believe you have information about anyone who carries a weapon please report it to Thames Valley Police online or by calling 101.”