Re: too much food?
It's hard to say what you LO's enjoyment of solids means for his breastfeeding future. Some babies who love their solids do wean early, but there are also plenty of babies who love solids and also love to nurse, and continue to nurse for years after solids are introduced. If your baby actively enjoys nursing, and seeks the breast for comfort when he's hurt or sleepy, then I think there's a good chance he'll continue to nurse even if he starts eating a ton of solids.
It's really hard to offer even a rule of thumb when it comes to the amount of solids a 9 month old should consume. I think you're stuck with "if he's eating enough solids that he's nursing less or less enthusiastically, then he's eating too much."
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"