I commuted everyday in Vancouver on a Honda CBR 125R, 33km each way, half of it on the freeway. It had 11.5 HP which is a bit more powerful than the 8.9 HP Grom. The top speed was about 132 km/h indicated, 120 GPS verified. 0 to 100 km/h was roughly 20 seconds. I loved that bike though. It averaged about 3 L/100km or 78 MPG, impressive considering I was WOT on the freeway half the time and hypermiling was not on my mind. It did get more fuel efficient as winter turned to spring.
Here's my Fuelly log (I don't go here often):
Lil Sport (Honda CBR125R) | Fuelly
It looks like a CBR 250R, but a couple of inches shorter: