Chol Hamoed is like Yom Tov as far as shopping goes. Food that you need for Yom Tov is allowed. I once took my children to Manhattan on Chol Hamoed and they wanted to buy some little things that we don’t see in our neighborhood. My husband didn’t think I can buy them, so I called a Rav. He told me that it’s forbidden.
Sefiras Haomer is not the nine days.