>>Can I apply for divorce in UK court from Canada?
It is unlikely because in order to be able to petition for divorce in England you or your spouse need to be either domiciled or habitually resident here. I suppose your spouse may be habitually resident here even if you move to Canada but it rather depends upon how long he has lived here without interruption.
>>OR
Can I leave the country soon after I apply for divorce/while divorce is in progress in the UK court?<<
Yes, provided the jurisdiction requirements were met at the time the divorce petition was issued.
>>During divorce process, am I required to be physically present in UK court at any stage?
Not normally, no, although if the divorce was defended you might be required to attend.
>>During divorce process, can I use dependent visa to travel in and out of country if required?
You would need to speak to an immigration lawyer about that.