The answer is a firm “maybe”. You need to ensure that your UV bulb is producing sufficient output at the correct wavelength, and like fluorescent bulbs, they get weaker with age. The UV won’t pass through objects to sterilize anything in shadow, so you need to make sure you expose each surface for long enough (at least 10 minutes). It won’t be able to get into cuts, cracks, or pinholes in your stoppers. It also won’t necessarily pass through glass vials without losing some intensity. Additionally, if your hood glass isn’t UV coated, you’ll get a sunburn if you’re standing in front of it.
In general, I don’t recommend this approach. In the lab, we treat UV as an insurance policy, not a primary sterilization method.