No, they are two different cartridges. 9mm is a semi-automatic cartridge and .38 caliber is a revolver cartridge. As a general rule, no ammo is "interchangeable" with other ammo. Some guns will fire more than one specific cartridge, such a the .357 magum, but each type of ammo is different than each other type.
No.
NO
the 380 is a 9mm short
Yes, 38 caliber ammo is available.
yes
Pretty close to the same in ballistics. The 9mm is used much more commonly.
gun shows, custom ammo makers
no, although the diameter of the bullet is about the same .356 for 9mm and 357/358 for the 38 cal. that metal cases will not interchange with other guns. i.e., the 9mm case does not feed in a 38 nor will a 38 feed in a 9mm..................
.38 S&W. This is NOT .38 Special.
No. Never attempt to fire ammo in a weapon not designed for it. Dangerous.
Yes, ammunition is made for it.
Generally speaking, no. .38 auto and 9mm para are different rounds. With only a few exceptions, you should never fire any ammo in a gun other than what the gun is designed to fire.