Remove Java 9

Author: alysbrooks

.circleci/config.yml

@@ -34,10 +34,6 @@ jobs:
     executor: clojure/openjdk11
     steps: [{checkout_and_run: {clojure_version: "1.10.1"}}]
 
-  java-9-clojure-1_10:
-    executor: clojure/openjdk9
-    steps: [{checkout_and_run: {clojure_version: "1.10.1"}}]
-
   java-8-clojure-1_10:
     executor: clojure/openjdk8
     steps: [{checkout_and_run: {clojure_version: "1.10.1"}}]
@@ -47,5 +43,4 @@ workflows:
     jobs:
       - java-15-clojure-1_10
       - java-11-clojure-1_10
-      - java-9-clojure-1_10
       - java-8-clojure-1_10