A scan tool may not do it as the correct method for a '99 on up Volvo is to have the code(s) checked, cleared through Volvos dealer PC known as Vadis. Disconnecting the battery won't work.
I wouldn't advise buying a generic scan tool for your '99 car if it doesn't do the trick as you'ld be wasting money.
The correct way is to have your dealer read, clear codes, like it or not.
You can't "remove the light" as the topic implies but the codes must be cleared, problem fixed before passing any emisions tests.