Your Toronto stations are "very" strong, they'll come in on a 91XG aimed at Buffalo anyway. You probably do not need an additional antenna unless you absolutely have to have the CHCH on UHF 15.
Until very recently, I lived about 10 miles from a million watt channel 14 transmitter that was about 45° off-axis to the aim of my 91XG. I still had to suppress it with a notch filter to keep it from overloading some of the amp's that I tested at home in order to equalize the signal powers.
In a similar vein, you likely do not need a separate VHF antenna for CFTO on VHF 9. Put the 91XG up there and see what you get and see if you actually need the second antenna before doing anything more.
Now, long time readers know I rarely suggest using the "wrong" band antenna, but I'll simply submit that I've had a LOT of time to experiment with these scenarios so I do have experience and data to back up my suggestions.
