battey problems or alternator problems

so recently i have been having issue starting my 2001 honda fourtrax. the starter turns very slowly or i just get a click. if i jump it the starter turns just fine. i charge my battery the other day and it has drained again. ( key left on). i tried charging it again and the battery will not charge. when i used my multimeter when it was running last week i had 12 or so volts on the battery itself and them it would pull down to 9 while starting and then when machine was running i would have around 14 volts. i dont want to throw parts at it and am hoping its just the battery . how can i verify this. my manual starter was all seized up from previous ownwer so i need to buy a whole new one . looks like ive got to jump it now in the mean time. any help would be appreciated
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