Jess, this could be due to the ear wart affecting his balance, but changes in normal behaviour can look to us to be something worrying, when in fact, to the hamster, it`s something of a change that they easily adapt to. My robo Fred (over two years old now) started to `spin` a few months back, yet he snaps out of it whenever he wants to and runs about, sits still to eat and drink, sleeps his normal patterns of sleep and runs about like a loon during the night! He also goes to a corner, stands up and does a few stand ups and circles and then scoots off again. He still runs in his silent spinner fine as well.
I would suggest not worrying too much about this behaviour change, but the growth in his ear will almost certainly be more problematic just because of where it is located. It could be blocking his hearing on one side for example. I`m pretty sure my Fred has either hearing loss or his eye sight isn`t great because he `lunges` and `squeaks` in attack mode if anything gets too close to him, so I believe he does have some kind of deterioration in those areas too, although there is no way to test this clinically.
Emi should continue on as well as he can regardless. Just keep everything in the same place because moving things about might cause him upset. I leave Fred`s layout exactly the same and he knows where everything is within a millimetre! I cleaned his bedding area late yesterday afternoon and it was like dodging a bullit!!!
But afterwards, he was excitedly running in and out, checking his fresh bed and basically, doing what he normally does. x