Baby doesn’t eat anything but the yogurt

My baby is 8.5 months old and formula-fed. We started introducing solids around 6 months, but he has shown no interest. At this point, he will only open his mouth for yogurt or blueberries—anything else is a firm “no, thank you.”

We’ve tried everything: purées, adult food, finger foods.

What has your experience been like? What could we do differently?

Our pediatrician mentioned that by around 9 months, a baby should be eating two proper meals, but we’re not there yet.