Hi.
Right now the setup you do on myCRED the first time you install the plugin is what is used. So if you setup myCRED to use decimals you can not change it to no decimals later.
In case you can not re-install or do not feel comfortable with adjusting SQL tables on your own, the easiest solution would be to filter how points are displayed by always displaying points without decimals.
This is done via the mycred_format_creds filter which fires just before points are displayed. Here is a quick example of how you can remove decimals:
add_filter( 'mycred_format_creds', 'remove_mycred_decimals' );
function remove_mycred_decimals( $amount ) {
return number_format( (int) $amount, 0, '.', '' );
}