For the 1st year of life: a baby's PRIMARY source of nutrition is from breastmilk or Formula. NOT solids and not other liquids.
Solids... is NOT as nutritionally dense... as breastmilk or Formula.
Nurse/give bottle, on-demand.
Day and night.
Especially at growth-spurts.
Do not make, solids his main source of intake.
For the 1st year... a baby does not have to... eat solids 3 times a day like adults. It is merely an introduction... to eating. Not their main, course.
Him waking once a night to nurse, is normal.
My kids at that age, were waking every 2-3 hours, to nurse. I did so.
I nursed them, on-demand. Even if they were on solids.
I never... nursed them according to a 'schedule.'
When nursed according to a schedule, a baby does not get what they are needing... per their growth-spurts or daily fluctuations of hunger.
Hunger, is not the same everyday, nor predictable. Some days a baby needs more nursing, than other days. That is why, nursing according to a 'schedule' is not recommended.
This is also, per our Pediatrician.
Always, nurse or give bottle... BEFORE solids. Which you do seem to be doing. Because otherwise, a baby will be too full to nurse, after solids.
9 months old... is a growth-spurt time. And they need, more intake in terms of nursing/or their bottle.
This is normal.
My kids had GINORMOUS appetites, per nursing. And they grew like weeds. I simply nursed on-demand. 24/7. At night too.
If you are giving a bottle, to replace direct nursing... sometimes, this will decrease your milk output.
Unless you do have ample milk production.