"Stronger" isn't a good word here.
Given the most common D and 9V batteries, it's more a question of "different" than "stronger".
The 9V has a higher voltage, while the D cell has a bigger capacity. What'll be best depends on what you need. It's like trying to decide if a sports car is better than a tractor.
Depends on how you measure it. A 9V battery is nine volts, while a AA is 1.5 volts, but they probably have approximately the same total power.
9v! More voltage, more strength! Many 9v batteries merely have 1.5Volt cells jammed together to make 9V!
no
A car battery has six cells each producing two volts. A 9v alkaline battery has six cells each producing 1.5 volts. There are some obvious differences, like that a car battery can put out hundreds of amps and a 9v alkaline can only put out hundreds of milliamps, a 9v battery weighs 45 grams versus 45 pounds for a car battery, and so on.
you better not. you need a 9V regulator for this, not a resistor!
No.
no
You can buy 9V batteries from almost any supermarket
very
use inverter
yes the invert mini takes 1 9v battery. it is in the grip frame. you should get a 9v with the gun/
Current I = V/R V = 9V R = 100ohm I = 9V/100ohm = 90mA
No.