The word "Creole" indeed has many meanings, but in the context of discussing Zydeco music, it is essential to realize that one common contemporary use of the word "Creole" is to describe the community of French-speaking African-Americans in Louisiana whose culture gave birth to zydeco music.

The zydeco music of these Creole people is a sort of hybrid consisting of equal parts traditional Cajun music on the one hand and New Orleans rhythm-and-blues on the other.

Zachary is white and ethnically Cajun (Acadien). However, his music is a lot closer to rock 'n' roll than that of traditional Cajun artists, and is stylistically almost identical to the music created by black zydeco artists. So, it's reasonable to describe him as a "Zydeco" artist (musician) but not as a "Creole" (person).

More on vocabulary: "Creole" comes from a Spanish word "crillo," meaning pertaining to the first generation of non-native persons born in the New World. It was originally used to describe offspring of European settlers (Spanish and French), but eventually came to include people of African ancestry (and/or half-European and half-African ancestry) as well. Creole culture would be understood to refer to the entire colonial lifestyle, including slavery, plantation life, etc. Hence the confusion over whether it describes white or black people or both.

The term "creole" is not limited to Louisiana. Indeed, the mostly-French patois which serves as the language of Haiti is called "Creole."

In Louisiana, the word is variously used to describe several very different groups and their cultures:
~ The lily-white urban culture (especially cuisine) of old (pre-Louisiana-Purchase) New Orleans;
~ An elite faction of light-skinned African Americans (actually French-African Americans) with long-time roots in New Orleans society;
~ The rural, dark-skinned African-American people of southwestern Louisiana who gave us Zydeco.

Among white Louisianans of French ancestry, "Cajun" and "Creole" are mutually exclusive terms, and many Louisiana French surnames are generally recognized as being from one group or the other. Cajuns are historically a rural people, and Cajun cuisine, etc., is definitively "homestyle." The old white "Creole" society of New Orleans was urban, haughty, and status-conscious. (Both groups knew how to eat, by the way, and came up with some great recipes!).

PS: Zach's last name is pronounced in the French manner, "Ree-CHARD," not "RICH-erd." He has been described as "the Cajun Mick Jagger," among other things.