0.9% glucose solution means there are 0.9 g of glucose per 100 mL water.
The concentration is required per litre for molar concentration:
0.9% glucose solution contains 9 g of glucose per 1000 mL or 1 L of water.
Molar mass of glucose is 180.16 g mol^-1 so 9 g = 9g/180.16 g mol^-1 = 0.05 moles
1 L of water contains 0.05 moles of glucose so molar concentration is 0.05 M or 0.05 mol/L