Coin exchange in Osaka or KIX airport

Can I exchange my yen coins for bills anywhere before returning home to Canada ?

Use them at a store or feed them into a ticket/vending machine.

I use all my coins, (except 1 yen coins) to top up suica/icoca cards.

Currency exchanges will not accept coins and will only return bills, so you will have Japanese Yen returned to you as change that didn't make a whole USD. As previously said, use it at vending machines, shops or keep it as souvenir.

It's not that easy to trade coins, but they are easy to spend. Just start paying for all your cheap purchases with coins your last day to clear them out. Things like coffee, lunch, snacks, souvenirs at the airport, etc. I think I ended up with about 2500Y in coins my last trip and I bought lunch and some cheap souvenirs at the airport while waiting to depart. You'll probably still have 200 y or so of random coins, but those can be souvenirs themselves.

Thank you everyone for your advice. 😊