Like the others who have weighed in, I didn't have too much trouble with it. I bought a reclining couch specifically for recovery from the hip resurfacings (had one done last month, the other booked for next month). You can "cheat" your way down and up from a chair of reasonable height by using the chair arms, rotating slightly toward your non-operated side, and keeping your leg straight as you lower yourself to the chair. When getting up, do the same in reverse, scooting forward till your butt is on the edge of the seat, roll slightly toward the non-operated side, straighten your leg, and push up with arms and non-opperated leg. This also works for getting in/out of a car and on/off a low toilet seat if the need arises. The bigger trouble for me was not letting the leg come too far toward the center. You get the hang of it fairly quickly, using a pillow between legs while sleeping or riding in a car, but it's easy to forget, and the stretched muscles seem to involve those that help stabilize the leg when "under load." As a result, it kind of wobbles back and forth under strain and some of those wobbles are toward the center which produces a sharp twinge of pain, at least for me.
Yesterday was 6 weeks post-op for me, so the 90 degree restriction was officially lifted. I've been working for 3.5 of them, driving myself, and yesterday celebrated the occasion by going for an 11.5 mile bike ride. I took my mountain bike, which has a bit less aggressive posture than my road bike but still gets well past 90 degrees at the top of each pedal rotation. I had zero pain in my operated hip, but some in my other hip and a lot in my neck, which encouraged me about the prospects of my two remaining surgeries.
Long story, short - I wouldn't worry too much about the 90 degree restriction. I didn't find it terribly limiting.