I personally don't think so.
I think Soma just figuratively sees Akira cheering him on while he pursues his dream.
Also, I don't think Akira was trying to kill Soma. Notice in the end that the neighbor said he thinks he might have made a mistake. I think Soma would've been able to awaken his sixth sense somehow and been able to see Akira again...but we'll never know!! (TT.TT)
No, I think Akira was able to let go and move on to the afterlife or something like that.
If he was still roaming around like that this manga would be 1000x more heartbreaking than it already is
Wait so is Akira still roaming around lonely? Was he really trying to kill Haruto?