Yes, you can give your 9-month-old baby laxatives like Laxaday if other methods have not been effective in relieving constipation. It is important to try increasing breastfeeding frequency, offering small amounts of water during meals, and massaging the baby's stomach to help with constipation first. If these methods do not work after a couple of days, you can consider using a laxative like Laxaday as recommended by your doctor to avoid any potential serious issues.