To be precise, let's look at the rpm/v rather than T or R.
The rpm/v (KV) of this hobbywing 9T brushless motor 4300. If you make reference to Novak brushless motor, the KV of 10.5R is 4200. So, a 9T hobbywing brushless motor should be a bit faster than a Novak 10.5R.
My DF03 also equips with this hobbywing 9T brushless system. My feeling is, it 's rotating speed is almost equal to a 13-15T brush motor (but our scentific prediction concluded it is a 10.5R (=21T) motor.)