Will i need a clutch kit with 27 or 28″tire install

I have a 2011 sportsman 850 xp with eps. I am looking at the kenda Bearc claw HTR’s and i see some people have done a clutch kit when putting 28’s on there quad. Do i have to do a clutch kit? what happens if i put the tires on and dont do the clutch? Will the stock clutch slip? I have read some threads that say that the clutch kit takes off the top end. Is there a clutch kit that will keep everything the same? I have also read that with any tire 9" or wider that i will run into issues with the control arms hitting the tire which i assume a spacer would fix that problem. Is there anything else i should have to do to put these tires on?