If a package was sent off from Peru to California, yet its a 9 hour flight then why does it take 2 weeks to arrive to California?

Because it doesn't go directly to the destination. +It has to clear customs before it can be delivered and that can take a lot of time.

Because they don’t take just your package direct from point A to point B.  

It has to go through customs. And once it hits the USA it may not go direct to California. There are different distribution centers it must pass through. 

I would say two weeks isn’t bad 

It can sit in a Lima post office several days before the One Truck, every 10 days, heads out to the airport. Same once customs gets their hands on it.

Parcel goes to Customs for inspection.

They do what they do on their schedule.

When done it the goes across the aisle to the Postal sorting plant in the same building.

At that point a few more days to you.

The way it has been for a very long time.

The number of flights have been reduced and mail shares space with the luggage.

Your parcel could wait days before it gets on a plane. Just being sorted for next flight out does not mean much. It waits its turn for some space.

Two weeks is NORMAL for mail from South America. Some is faster and some slower.

Because the package, unlike a person who is travelling on the plane, is not carried directly to a plane which takes off immediately and then when the plane lands the package is not carried directly to where it's going. It probably didn't go on a plane at all. Maybe it went on a ship. They're slower.

The mysteries of transit time . . . . . .

Transit time works differently from sidereal time, it is not linear, in fact it is shaped like a bent donut, or bendy straw. Time passes very differently in Transit, its a bit like waiting in for a delivery, or tradesman if you are a biut posh. This is because you have edged closer to Transit time and weird things happen, like time slows alsomst to a stop but if you are not standing right behind your door, it passes in a flash and you get carded.

Is the closest analogy I can make without a lot of boring equations.