I got info from the Rally Poland Facebook that when you buy online the ticket, you'll get a voucher you need to print out and take with you to the rally ticket sales point where you'll get your ordered kit. Everybody complained on Facebook that 2009 there were really long queues for getting tickets...
So not very good solution but no other options. I have been on Rally Finland more than 20 times as this is close to Estonia and this summer we will go to Rally Poland for a first time. We'll see afterwards was this a good idea or not.