My personal opinion: The industry reduced recommended oil change intervals based on trying to get customers to change more often, not based on science. The supposed "recommended" 3,000-mile change intervals you see from dealers and shops is a travesty that wastes money and harms the environment. I saw this when Toyota reduced the interval from 7,500 for my '02 Camry V6 to 5,000 for my '08 Avalon, practically the same engine. My response has been to use synthetic oil, which lasts more miles and has no breakdown over time, and waiting 7,500 mi. or longer to change. My '02 Camry has 185k mi. and is going strong, my '08 Avalon 85k mi. and I expect the same longevity.
So I was thrilled to learn that my TAH came with synthetic oil and 10k recommended change intervals (for normal driving). I am skeptical of the reported reduction to 9k. I intend to follow the recommended schedule for as long as Toyota is paying for the oil changes (2 yrs 25k mi., which is just two changes), so I guess I will check to see if the dealer will replace it every 9k. Then I will wait at least 10k miles regardless of what the dealers convinced the engineers to say to get people in the door more often.
This opinion valued at $0.02.
