Twenty-year-old centre Joseph scored two tries, while 21-year-old full-back Homer kicked 10 goals from 10 attempts - six penalties and four conversions - to finish with 26 points.
"These boys are the future - and they are the present as well," said Booth.
Homer took his tally for the season to 67 points from four matches and Booth said: "We're all guilty of making this game more difficult than it should be some of the time.
"But the boys scrummaged exceptionally well and Tom paid the forwards back by keeping the scoreboard ticking over."
Joseph, who scored two tries as Irish secured their bonus-point win, will face stiff competition for his place when close-season signings Shontayne Hape and Joe Ansbro return from their World Cup campaigns with England and Scotland respectively.
But Booth said: "He's gone a long way at good pace for his tries.
"But JJ isn't a surprise because of what he did last year. We know exactly what he's capable of.
"He's one of those who we are fast-tracking with experience because he can deal with that."
Booth was also pleased with New Zealand international flanker Bryn Evans' first start for Irish, 10 days after arriving in Britain.
"He's an All Black so he's going to have quality," Booth said.
Newcastle head coach Alan Tait did not hide his disappointment following his team's performance.
Tait said: "You just can't believe some of the things that went wrong.
"The guys need to put their hands up and ask why our scrum went from good to non-existent.
"The first try was through the middle of our defence but the rest we just coughed the ball up.
"Our attack just fell to bits. It's unacceptable and I've told them so."
Newcastle had lock James Hudson sin-binned in the first half and replacement full-back Will Chudley in the second, and Tait said: "You forget how much that takes out of you.
"In attack we were just woeful. At the end we came back and scored a good try and you just wonder why they didn't attack like that more.
"We will just have to work harder in training. We will have more live contact on Tuesday so it gets more tasty."
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