Does hypoplasia of the left anterior cerebral artery a1 segment increase risk for aneurysm or ischemic and hemorrhaging strokes? If yes why?

It shouldn't. Hypoplasia is commonly a normal finding. It should not increase risk of any kind of stroke.
Congenital variant. There is no relationship to aneurysm presence, and lifelong collateral flow through other vessels has previously been well established. Stroke risk is based upon presence of hypertension, diabetes, heart disease, high triglycerides, high homocysteine, and smoking. Your doctor can screen you for potential future problems. Do not worry about your artery.