This is very nice to have especially when devices take up 3 plugs just to plug in 2. Also having the USB plugs on the top that are rated at more than just 1 amp each.
So after plugging in 9 devices and your phone and heaphones to charge, how quickly are you apologizing to the firefighters on the local news? 20m-300m-6M-2y?
If your homes circuit breakers / line fuses habe not been tampered with, there should be no problem. This device plugs directly into your wall outlets, so if your nine devices total up to more than your circuit protector (usually 15 Amps) the breaker trips / fuse blows. The “too many devices” problem comes in on EXTENSION CORDS that have multiple outlets, are are not rated for 15 Amps (or preferably more). If it’s only rated 8-9 Amps (at its’ full length) when you plug in 14 Amps of devices the wires can get hot enough to melt the plastic insulation, if the fumes from that don’t asphyxiate you, the exposed wires can spark and start a nice house fire…
These devices are very handy and quite safe. Most of the time people are plugging in “wall warts” - block transformers - to power / charge thier digital devices. If the output is 5 Volts @ 5 Amps (that would be a very high rate charger) that is still only about 25 Watts and (if conversion were loss-less) drawing 1/5 Amp off the wall. Even at 50% efficiency (very poor performance, normal is 80-85) the device is using less than 1/2 Amp. So powering nine similar devices is less than 5 Amps - no problems.