Hi
At this age they don't need solids, their primary food is milk right up to a year old so rather than focus on how much he eats think more about his experience of food, what you are teaching him about food and setting up good habits around food. Think more about how you want him to eat in the future rather than how much he eats now. So I'd make the future goal something like this:
a variety or healthy food
a balance of food groups
eating to his fill and not beyond
sitting at the dining table with the family
taking part in family conversations and socialising during meals
even helping to clear up at the end of a meal
Babies and children love to copy mummy and daddy having him at the table during meal times and eating your own meal, letting him see what you eat and how you enjoy it, learning the social aspect of table manners, conversation etc, all of these things can be modelled right now and he can just have small tastes of food until he wants no more. Distractions during meal times, praise for eating, and a requirement to eat a certain amount or finish a plate can result in excess weight in the future, babies are very good at self regulating their calorie intake so it is unwise to over ride that natural ability. If you set up how you want meals to be and have low expectations, making allowances for his age, then the actual eating will happen when he is ready for it.
hth
(btw with clearing up, mine liked to help me gather all the bits of food off his tray and pop them back on the plate or in the bowl, it's not something to force, just model and let him join in when he is willing)