The owners manual on this specifies a 5W30, but then, in very fine print, it suggests that a 0W30 or a 5W40 should be used for hard driving.
It mentions A1/B1, but it's a 20 year old manual, and subsequent TNN recommend the A3/B4 after a ton of Volvos of that vintage had major sludge issues.
For example: https://www.volvoxc.com/0/resources/how-to/pdf/01-23-09/TNN,%20Lubrication%20System%20Contamination%20Cleaning.pdf
Volvo went to a 7,500 mile OCI that year, in partnership with Castrol, and specified a euro long-drain oil. But...
Volvo NA told its dealers, "use Castrol 5W30" and they promptly went out and bought bulk, conventional, 5w30 and used that on every new Volvo. A few years later the sludge parade started.
So, use a long drain specified oil, like the above mentioned, and avoid the ugliness that resulted in Volvo having to do a recall and issue the TNN.