Unlikely. The web applet needs a browser with Java applet support, and 3D PDF only works in Adobe Reader/Acrobat, not in Apple's built-in PDF rendering (such as you find in Safari, Preview, and Quick Look).
We tailored the Collada export in our latest releases to work in iBooks Author for viewing iBooks on an iPad, and Preview on the Mac. I don't think we looked into Keynote - but maybe it supports the same 3D viewer these other two apps do?