Can a deviated septum cause blurry vision at times, or pain in the glabella/ethmoidal sinus?

Unlikely: A deviated septum is unlikely to cause the symptoms you are describing however sinus inflammation from allergies or infection or trauma can.

It can cause: sinus issues but probably it will not effect the vision.

Possible: Deviated septum lowers the threshold for rhinitis to cause sinusitis/sinus pressure. Surgery is the only cure for deviated septum (as long as scarring can be minimized), but several treatments are available for rhinitis. Efficacy depends on identifying cause (allergy, infection, irritant exposure, hormone changes, etc.). If associated, the blurry vision would occur simultaneously with sinus pain.