Is there a passenger air bag shut off in my Lexus 450h? Where?

https://drivers.lexus.com/lexusdrivers/resources/manuals-warranty Go there for a copy of your owners manual where you can explore all the functions available to you. As a rule of thumb, the occupant detection system in the passenger seat should detect his weight automatically and shut the passenger frontal air bag off. There is an indicator light for that which will illuminate. If the child is over 100 pounds, it is likely safe for him to sit in that position with the air bag on, and the system will not shut off.