removed node_js 9 from .travis.yml

(not supported by node-sass so we exclude it complete)

.travis.yml

@@ -2,7 +2,6 @@ language: node_js
 
 node_js:
   - 8
-  - 9
   - 10
   - 11
   - 12
@@ -11,11 +10,6 @@ env:
   - INSTALL=yarn
   - INSTALL=npm
 
-jobs:
-  exclude:
-  - node_js: 9
-    env: INSTALL=yarn
-
 matrix:
   fast_finish: true