An unlicensed, drug-affected learner driver was doing more than double the speed limit when he crashed into an airport shuttle bus, killing his teenage passenger, a Perth court has been told.

Steve Mason Mourish, 19, was driving a stolen car and trying to avoid police when he ran a red light at 150 kilometres per hour in Kewdale in April last year and collided with the bus, leaving its driver with serious injuries including three broken ribs and a fractured spine.

Mourish's passenger, 16-year-old Jack Meier, was severely injured in the crash and died later in hospital.

Jack Meier was killed when a car being driven by Steve Mason Mourish crashed into a shuttle bus. ( Facebook: Jack Meier )

In the Supreme Court on Thursday, Mourish pleaded guilty to a string of charges including manslaughter, dangerous driving causing grievous bodily harm and driving without a licence.

He also admitted a burglary on a home in Cloverdale about three months earlier, in which he and an accomplice had tried to steal presents that were under a Christmas tree.

He was on bail for those offences when he stole the car from a home in Oldbury in Perth's south.

State Prosecutor David Davidson said police spotted the car in Belmont just before the crash but Mourish failed to stop when they tried to intercept and drove off at high speed.

Police saw him soon after on Abernethy Road in Kewdale doing 150kph in a 70kph zone, but he again sped away from them, before going through the red light and crashing into the bus.

The scene of the crash in Kewdale where the car collided with an airport shuttle bus. ( ABC News: Tom Wildie )

A deprived, disadvantaged, abusive childhood

The court heard Mourish, who had not yet gained his driver's licence, was under the influence of cannabis at the time, which experts concluded would have impaired his ability to drive.

Mourish's lawyer, Simon Freitag, SC, said his client was "traumatised" by "the magnitude" of what he had done. At the scene of the crash, when asked by paramedics if he was hurt, replied: "My heart hurts. I'm sorry I killed my brother."

Jack Raymond Meier died when the vehicle he was a passenger in collided with an airport shuttle bus. ( Facebook: Jack Raymond Meier )

Mr Freitag said when Mourish also told police he was sorry, an officer retorted, "That's what happens when you steal cars" — something Mr Freitag described as being "one of the coldest things" he had heard said at the scene of an accident.

Mr Freitag told the court Mourish's upbringing was marred by "severe deprivation, disadvantage and physical abuse", and before he turned 18 he'd had 76 different foster care placements.

"His life was a very desperate and sad one before these offences," said Mr Freitag.

"His education has been incredibly patchy because he has moved so many times with the different placements."

Reports presented to the court concluded Mourish had a "cognitive impairment" which may have affected his judgment and the decisions he made.

There was also a suggestion he may have foetal alcohol spectrum disorder.

Mourish will be sentenced in March after a new report is prepared to determine if he does have the disorder and, if so, what impact it may have had on his offending.

He was remanded in custody.