for those still interested and to make things even more confusing
oh and that 9,6 billion people limit is BS (bad science 
).
the planet’s carrying capacity is changeable, it all depends on the sustainability of human practices and their relationship to the environment, for example, if we were all still hunters and gatherers, we would need much more land to sustain the same number of people, because the resources we were consuming would grow naturally. But if we can sustain and grow that which sustains us, then there is no limit.