If my employer pays me in a currency different from the one I use, is it worth while to buy financial instruments to offset changes forex rates?

This isn't an ideal situation to be in. You know what your expenses over the year will be, but don't know your income. How much that matters to you will depend very strongly on how much volatility you can absorb on a monthly basis, over a year, and over your lifetime.

In theory, you could say that the rate moving up or down over the year is a coin flip - CADUSD is a frequently traded currency pair, so it is reasonable to assume the market is able to efficiently price the current exchange rate, roughly incorporating all publicly available information into it. This means again in theory, that the cheapest option to resolve your problem would be to ignore it, accept the risk, and take the wins and losses over time as they occur. The problem with this is that a 10% increase in your effective-CAD income probably doesn't help you as much as a 10% drop in your income would hurt you.

For example - if your fixed monthly expenses are say $5k, including your mortgage/rent, car, food, etc., and your income is $5.5k, then without fx risk, you have $500 per month to save. With fx risk, a 10% drop in income due to weakening USD would leave you with just $5k in income, barely meeting your fixed expenses, possibly causing you to start to incur monthly debt or lifestyle changes. Meanwhile a 10% rise in income would mean you had $1k per month to save, which is great, but perhaps not as life-changing as an equal chance of suddenly going paycheque to paycheque.

The simplest approach to deal with this would be as @Kate suggested, to automatically convert your USD paycheque into CAD once you receive it [shop around to make sure you're getting a rate as close to the bone as possible, this could be worth 1-2% of your salary compared with just assuming your bank's rate is fair]. But more broadly, that doesn't address the forward-looking risk of volatility of income not yet received.

There are many ways you could address this risk. For example, you may even want to consider having your mortgage converted to USD, assuming you have a mortgage [may be possible with your bank, if you show them consistency of USD income, but probably only possible if you already had a high % of equity in your house]. Getting your large fixed expenses in the same currency as your income could take away the largest concerns over a volatility, and if you are comfortable with some minor fluctuation of the remainder, that would deal with the bulk of your fx risk. Keep in mind that if you ever changed jobs or stopped earning USD, or worst of all needed to move, suddenly you would have a CAD-valued house and a USD-valued piece of debt, and if the USD had strengthened in the meantime, you could find yourself underwater on your mortgage overnight. If you are considering this at all, be very sure you understand the risks associated.

You could perhaps do the same thing with your car loan (if applicable), or any other negotiated fixed expense. If you have a good enough relationship with your landlord (if applicable), they may even prefer you to pay them in USD than CAD, if they themselves are investors with primarily USD interests.

Getting beyond a potential restructuring of your personal financial affairs, I would suggest that buying some type of long-term fx swap style arrangement may be overly complex. If you are comfortable with getting more 'exotic', there are possibilities available to you, but unless you are willing to put the research in beforehand to gain comfort with this, I would say this is too complex to suggest to someone asking questions about it at this level.

More than anything else, I would suggest that you try even harder to build yourself a comfortable cushion in your monthly budget, so that you have the ability to absorb periodic downturns if and when they occur.