Absolutely! Just make sure to thoroughly dry the surface before sticking the tesa Powerstrips on the wall.
The IXXI itself is printed on Synaps: high-quality, tear-resistant, and moisture-resistant material, so it can withstand humid environments. We don't mean literally in the shower, but a bathroom space is perfectly suitable for an IXXI!
Standard tesa Powerstrips are included with your IXXI. Are you planning to attach your IXXI to tiles? There are special tesa Powerstrips for tiles available for purchase, which you can find at various large hardware stores.