What is the effect of using wrong DC adapter to power on an electrical device?
In general the effect depends on the device and power supply.
In general, connecting a 9V supply to 5V device could damage it immediately, or in long term, but it is impossible to say without seeing the schematics of the device how much excess voltage it can handle.
However, you are using USB devices, so the above does not apply.
In this case you simply used device with 5V USB output to a device that can take 5V USB input but also other voltages.
USB devices communicate which input and output voltages are supported, so a USB charger able to output more than 5V will output only 5V unless the charged device communicates and asks for higher voltage.