Looks like the Java 1.7/1.8 versions may be swapped in this documentation:

https://teiid.gitbooks.io/documents/content/admin/Migration_Guide_From_Teiid_8.x.html

JRE Support
Teiid 9.1 uses WildFly 10.0.0. Both the server kit and usage of Teiid Embedded will require Java 1.7+. The client driver may still use a 1.6 runtime.
Teiid 9.0 uses WildFly 9.0.2. Both the server kit and usage of Teiid Embedded will require Java 1.8+. The client driver may still use a 1.6 runtime.