Great question! There are always three aspects to consider when paying down debt: 1) the math, 2) personal bias, and 3) everything else to consider.
In your situation, the math is pretty easy. If you're paying 4.5% for the money and you're only earning 0.9%, it's costing you a net 3.6%. The math says you should pay off the loans.
A good example of where a loan makes sense today is buying a home. You can get a 30-year loan with an interest rate of less than 4.0% today, but houses are appreciated 16% over the last year. In this case, the money costs less than what you're earning on it.
Some people hate debt. Sometimes their parents drilled it into their heads to avoid debt. Sometimes they just learned from experience that they didn't like owing money to others. Sometimes people are fearful being a slave to others. If you hate debt, pay it off, especially since it's costing more than what you're earning.
Other use leverage effectively to build wealth, which is what you're doing. You're building up a savings program instead of paying off the loans.
Think about how you feel about this topic and factor that into the decision.
There is a lot to consider here. Taxes are one aspect. Student loan interest is tax deductible in many cases so you have to look at the after-tax cost of your loan. It's too lengthy to explain here, but your 4.5% loan may be costing you less after you factor in taxes.
Emergency savings. You should have enough savings to cover 3-6 months of expenses for housing, food, taxes, loan payments, etc. You should start accelerating payments to pay down your debt after you have enough in emergency savings. If you don't have to worry about paying rent, mortgage, other loans, etc, come up with a plan to pay off debt aggressively.
Here is an article I wrote that might help:
You can also search for "Snowball debt repayment plan" on the internet and find lots of resources.
There is no blanket answer that makes sense for everyone. I hope this gave you some ideas to formulate your own direction.