Is it ever the bike?

[TxDoc]

My road bike isn't exactly a go fast bike. Its a Cannondale Optimo from a while ago and weighs possibly in the 9kg range?

Hi Alexis,
yours is maybe not a very lightweight bike, but it can be fast... which is actually good news, meaning that maybe there's a few things that you can do with your bike to be faster

Now, to answer your original question of 'is it ever the bike?' - I guess I'm not with the crowd, but in my experience, provided that the bike fits, the answer has always been NO.
The main factors are bike fit and training.

Sometimes when people lament about their bike being 'too slow' - I offer to do small experiments, like field tests of 10 miles TT or so. I give them a lightweight race bike, or a TT bike, or lightweight wheels, or aero equipment... whatever they say "Oh, if I had 'so and so' I would go faster". And then we look at how the change of equipment affected performance. Most people come out surprised: they think that a bike 5 lbs lighter or lightweight wheels will make them 3 or 4 mph faster, and end up disappointed when this does not happen and all that is gained is like 6 seconds over 10 miles.
Most of what determines speed is the way you ride, how your body works, your power output, your position on the bike, etc - all of which are vastly improved by proper fit and efficient training.
Then yes, after all has been dialed in and the bike fits perfectly, the lightweight wheels and the Ti cassette and the carbon crank might shave you a few seconds at the end of the race. But a few seconds make more of a difference at 35-40mph than at 16-18, so unless you are battling within the top finishers already, a few seconds may not change much.

First things first... you mentioned that the bike 'fits' - so I gather that you already had someone fit the bike to you? If not, that is exactly where you start.
Maybe the frame fits, but if the overall setup is not perfectly right for you, you may be losing power. Overall setup being seat height, sea fore/eaft, stem length/angle, handlebars drop/reach/height, # of spacers, crank length, cleats placement, etc etc. If some of the above are not dialed in, you are actually using energy but some of the energy does not transfer to the pedals and is just lost. Seat/handlebar positioning and cleat positioning are often a big issue - a small change and suddenly your effort seems to pay off in terms of speed.
A good pro fitter will also discuss your positioning and technique with you - and tell you how your position and actions on the bike will affect power output. They may also give you exercises to do off-the-bike to improve strength and flexibility.

Another issue is that, depending on your style of riding, you may or may not have the right gear combinations on your bike. This is usually a subtle change but if you ride variable terrain with flats and hills and mountains and technical descents... well, it may also make a difference. That, we cannot know unless we know what crankset and cassette you use, and how do you ride/on which kind of roads.

My recommendation would be to check the fit first - see if there are shops that offer professional fitting services in your area, ask around for good recommendations, find a good fitter and make an appointment. It could be the easy way to change a few things on your bike and make you comfortable and efficient.

As per training, you mentioned training for 6 months but not how you train. That alone makes a huge difference. You may be working on the bike every day and not see any tangible improvement because you train focusing on an area and measure your improvement on another. For example, if you train for mileage base and measure improvement based on sprint speed - you may not see any change. Why? Because you work on A and test B. It's like teaching students: if you teach them A and test them on B maybe no student will pass. Our body is a student, sort of, and learns what we teach.
So, before you get disappointed about the lack of speed improvement, make sure that you are, in fact, focusing your training to achieve higher speed.
That also extends to your 'off-the-bike' training, i.e. fitness: make sure that your strengthening program is designed to achieve your goals.

One last suggestion - if your plan is to start racing, have you tried looking for a team? It is always better to race with a team as opposed to unattached. Also, teams often have deals with local coaches, so you could get some help for coaching, maybe fitting - and most of all you would get (for free!) the experience of your teammates to help you improve.

Good luck, and keep us posted!