Did you get the 35 lb rear facing version or the 40 lb rear facing version? The second option is better.
It is a good, budget, seat. You mentioned you need to rear face because your son is 8 months (which is absolutely correct). Did you know that you shouldn't be turning forward facing for several years? At bare minimum your son needs to rear face in the car until at LEAST his second birthday. After that, you should keep him rear facing as long as he fits (head up to 'even' with the top of the shell, and under the rear facing weight limit (35-40 lbs depending on the version you have).
The Scenera is a budget seat, so it doesn't have a lot of 'ease-of-use' features. If you can afford a more expensive seat, there are seats in the 130-150 range that will last a lot longer and are easier to install. If not, let's talk about the installation that you have.
What make, model, year, is your car? Is the seat installed in the middle, or outboard? Is it installed with a lap belt only, or a lap-shoulder belt? What locking mechanism are you using? (Does the belt lock at the buckle, at the shoulder, or are you using a locking clip?)
The seat is extremely safe and passes the same tests other seats do, but, as I said, it won't last as long and it isn't as easy to use as some other seats. If you want recommendations for those, even as something to save up for down the road, let me know. The important thing is that your baby remains rear facing for years to come and the seat is used correctly :-)
(ETA: re the above post, even if it's not legally required, any seat installed in the forward facing position should ALWAYS ALWAYS ALWAYS have the top tether engaged. It's a very important safety feature. For pre-2000 cars, top tether anchors can generally be retrofitted.)