a 900r16 stands at about 35 or 36 inches tall your 750s stand at about 31 or 32 inches tall, you will be looking for 2 inch lift with lock stops adjusted or wider wheel offset and remember :search:
I did have a search before posting but couldn't find anything definitive about 9x16s on a 90.
I will leave it be then, just I saw a set of 9x16 wheels with tyres on eBay and wondered if it would be a quick an easy way to get a bit more clearance.