Does the Nokia N97 support 32gb microSD?

MicroSD is the thing of the past, you won't find MicroSD bigger than 2GB. You probably talking about 32GB MicroSDHC.

All Nokia E series, N series and XPressMusic all support MicroSDHC. The known limitation of MicroSDHC is the limitation of its data format (which is FAT32). Somewhere close to 128GB.

If your phone doesn't enforce the restriction down to firmware (for marketing purposes), then 32GB MicroSDHC should be supported (if you can find newer and larger capacity of up to 128GB MicroSDHC, then it's all the same support).

I can't speak for N97 as I don't have one, but on my 5800 XPressMusic, SanDisk 32GB works fine.