Walk out using the overbridge towards NES bus stop, 5 minute walk. From NES , you'll get more buses, even at 930.
Any local person should guide you towards NES.
If you...
more... exit from main entrance of station, you'll reach Yelahanka old town, which has a big bus stand ,but buses don't start to majestic (kempegowda BS) from there. You'll have to further walk towards main road. From this bus stand you ll get buses to yeshwantpur every 5 minutes or more.