No.
The machine will notice that it isn't getting all the required voltage and won't run.
A: Disregarding the fact of different voltages there is the power to be concerned 9v x 1A = 9W, 15V X .8 = 12W. THE DEVICE WILL BE UNDER POWER.
Almost certainly.
Yes you can. It will just take a little longer to complete the charge cycle.
15v appliances
Yes, a small amount. Yes, but it's very low power. Hardly noticable.
-7
A electrical voltage of Fifteen Volts.
most computers use a standard 240 volt power usage, but 230 volts and 115 are also fairly common. laptop power usage can vary between 15v and 20+v
it regulates +15v constant at output.
somehow
11-15v from batt.
15(u + v - 2)