13 volts is too low with the engine running, it should be charging around 14.5 volts. So maybe you have a dud alternator and/or rectifier. 9.9 volts is also too low whilst cranking, indicating a run down battery. BUT, you said you've had it on a tender etc so battery should be fully charged, so most likely your starter is shot or has a bad connection, or the starter relay is faulty.
Sent from the bottom of ANOTHER empty whiskey bottle.
Chookbanger Mark II,
Street legal Blue Viking, 2017 model, bought 3/4/2017.
Street legal Blue Viking, 2014 model bought 3/4/2014, sold 3/4/2017 with 2850 km and 189 Hrs.
Yamaha Saggy Bottom Club member.
Other Yamaha Bikes Currently Owned
2016 YZ85 (sold)
2017 Grizzly 350 4x2 Auto Quad
Honda 2012 CB250
Honda 1999 CT200
Honda 1985 CT200 Trike