returning to Canada with US born children- waiting for citizenship card

[AmyRL]

I have three children- one born in canada two born in US. I am canadian born. I've applied for the citizenship cards for my two US kids (ages 9 and 7) but that will take a year to receive. What do I do in the meantime for my kids? We plan to return to Canada in 5 weeks. Will I need to get visas for them until they receive their citizenship cards?? I want to register them in public school- will they allow me to do so without proof of citizenship?

Thanks for your help!!

Amy