As per your given input your final output is highlighted above.
If you want v in the final output then use sth like this..

And instead of using split just us FS for the same

Code:

$echo "deploy_v11_9_1" | awk -F "y_" '{ print $2}' 
v11_9_1

or if you want only numbers then..

Code:

$echo "deploy_v11_9_1" | awk -F "_v" '{ print $2}' 
11_9_1

and please look this..

Code:

 
$ version=`echo "deploy_v11_9_1" | awk -F "_v" '{ print $2}'`
 
$ echo $version
11_9_1

Code:

$ version=$(echo "deploy_v11_9_1" | awk -F "_v" '{ print $2}')
 
$ echo $version
11_9_1

Both $() and `` are used for the same but $() is preferred over backticks.