Hey,
I opened up a personal account since I'm trading (and filing taxes) under an individual (non-business). In your case, I would assume you open up as a professional if you are trading under a business entity. However, I would double check with IB to see what their definition of "professional" because it can be confused with a "pro" trader (IE. insider, director, spouse of insider, etc...)
Currently, I'm trading as under "personal" and plan to file taxes under self-employed (if I make money LOL). This is because it's the simplest way so far. Once I get consistent and profitable with my trading, I'll eventually incorporate and file taxes as a corporation. The main benefits to doing so would be limited liability and decrease taxes. Some disadvantages would be cost and complexity for accounting (book keeping and tax reporting). I plan to do all the bookkeeping and tax reporting myself as I really don't trust accountants especially for the cost to pay them.
In general, there are 3 ways to file day trading taxes as a Canadian:
1) Self employment
2)Business Income
3) Corporation
**Also this is not to be confused with swing trading or investing as you can utilize a TFSA account for tax benefits. I'm talking strictly day trading.**
Check out these resources for the details:
https://bearbulltraders.com/course/technology-monday/lesson/broker-trading-platform-tax-services/topic/managing-taxes-for-canadians/