Thanks PMM. I failed to mention that when I landed in 2009, I had applied for my PR card, permanent SIN, Health card and opened a bank a/c with minimum balance- but have not used any benefits till August 2010. Does CRA treat someone having the health card/permanent SIN/bank ac as a Resident?
If you have a health card, CRA normally sees this as one proof that you are a resident for tax-paying purposes. But that's because to qualify for health care you need to be residing in Canada for at least 6 months per year, and residing in Canada for 183+ days per year deems you a taxpayer. But you were not a resident for 6+months, so you were not a taxpayer in that year.
The corollary issue is that you were probably not eligible for health care, even if you paid premiums, because you resided less than 6 months. Good thing you didn't get sick while in Canada!
Having a Canadian bank account is not in itself fatal; you can have one and still be a non-taxpayer, as long as you don't have too many so-called "secondary" financial ties to Canada.
Ditto the SIN card.